# Boat And Stream Questions Answers, Quiz, Exercise, Mock Test For Bank, SSC

Stream Boat Problems Practice Questions section is based on the problems on Streams and boats. The Stream Boat Problems Practice Questions section has all the diverse set of questions that may be asked in an exam that focuses on the Stream Boat section. Let us try to solve all the different kinds of examples of Boats and Streams in this section on Stream Boat Problems Practice Questions. Boat And Stream Questions Answers, Quiz, Exercise, Mock Test For Bank, SSC

## Boat And Stream Questions For Bank, SSC PDF

#### 1. Ram goes downstream with a boat to some  destination and returns upstream to his original places in 6 hours. If the speed of the boat in still water and the stream are 12km/hr and 5 km/hr respectively, then find the distance of the destination form the starting position.

A) 25km

B) 26.67km

C) 33km

D) 29.75km

E) 20km

Answer is Option D

Solution:

T = 2xD/(x^2 – y^2)

=> D = 119*6/2*12 = 29.75km

#### 2. A boat travels downstream for 14km and upstream for 9km. If the boat took total of 5 hours for its journey. What is the speed of the river flow if the speed of the boat in still water is 5km/hr?

A) 8km/hr.

B) 2km/hr.

C) 6km/hr.

D) 5km/hr.

E) 3km/hr.

Answer is Option B

Solution:

Let the speed of the stream be x km/hr.

Upward speed = (5 – x)km/hr.

Downward speed = (5 + x)km/hr.

14/(5+x) + 9/(5-x) = 5

=> x = 2km/hr.

#### 3. When a person is moving in the direction  perpendicular to the direction of the current is 20km/hr , speed of the current is 5km/hr. Then find the speed of the person against the current?

A) 10km/hr.

B) 15km/hr.

C) 30km/hr.

D) 25km/hr.

E) 11km/hr.

Answer is Option A

Solution:

Speed of the person = 20 – 5 = 15km/hr

Speed of the person against the current =

15 – 5 = 10km/hr.

#### 4. A boat goes 6 km an hour in still water, it takes thrice as much time in going the same distance against the current comparison to the direction of the current. Find the speed of the current.

A) 5km/hr

B) 3km/hr

C) 8km/hr

D) 9km/hr

E) 12km/hr

Answer is Option B

Solution:

Let the speed of the stream be x km/hr

speed of the still water = 6 km/hr

Downstream speed = (6+x) km/hr

Upstream speed = (6-x)km/hr

Now,

3[D/(6+x)] = D/(6-x)

=> x = 3 km/hr

#### 5. There are two places A and B which are separated by a distance of 100k. Two boats starts form both the places at the same time towards each other. If one boat is going downstream then the other one is going upstream, if the speed of A and B is 12km/hr. and 13km/hr. respectively. Find at how much time will they meet each other.

A) 10hrs.

B) 4 hrs.

C) 8hrs.

D) 6hrs

E) 7hrs.

Answer is Option B

Solution:

Downstream = (12+x)km/hr

Upstream = (13-x)km/hr

Time = Distance / Relative speed

Relative speed = 12 + x + 13 – x = 25

km/hr

Time = 100/25 = 4 hours

#### 6. A girl was travelling in a boat, suddenly wind starts blowing and blows her hat and started floating back downstream. The boat continued to travel upstream for 12 more minutes before she realized that her hat had fallen off. She turned back downstream and she caught her hat as soon as she reached the starting point. If her hat flew off exactly  2km from where she started. What is the speed of the water?

A) 12km/hr

B) 8km/hr

C) 5km/hr

D) 9km/hr

E) 10km/hr

Answer is Option C

Solution:

Distance = 2 km

Time = 2 * 12 (doubles ) = 24 mins. = 2/5

hr.

Speed = 2 / (2/5) = 5 km/hr.

#### 7. A ship sails 30km of a river  towards upstream in 6 hours. How long  will it take to cover the same distance downstream. If the speed of the current is (1/4)rd of the speed of the boat in still water.

A) 2 hrs

B) 4.5hrs

C) 5 hrs

D) 3.6hrs

E) 5.5 hrs

Answer is Option D

Solution:

Let x be speed of the boat and y be the

speed of the current.

Downstream speed = x + y

Upstream speed = x – y

x –y = 30/6 = 5 km/hr.

Now,

x = 4y

x – y = 4y – y = 3y

=> x = (20/3)km/hr and y = (5/3)km/hr

Therefore, x + y = (25/3) km/hr.

Time during downstream = 90/25 =3.6 hrs.

#### 8. A man can row 6km/hr in still water. If  the speed of the current is 2km/hr, it takes 4 hours more in upstream than in the downstream for the same distance. Find the distance.

A) 44km

B) 40km

C) 32km

D) 50km

E) 45km

Answer is Option C

Solution:

Let the distance be D.

Downstream speed = 8 km/hr

Upstream speed = 4km/hr

From the question,

Upstream = Downstream + 4

D/4 = D/8 + 4

D/4 = (D + 32)/8

D = 32 km

#### 9. The speed of the motor boat is that of the current of water is 36:5 . The boat goes along with the current in 5 hours 10 minutes . How much time it will take to come back .

A) 45/2

B) 41/6

C) 55/3

D) 38/7

E) 52/8

Answer is Option B

Solution:

S1/S2 = T1/T2

(36 + 5)/(36 – 5) = x/(31/6)

=> x = 41/6 = 6 hours 50 minutes

#### 10. In a fixed time, a boy swims double the distance along the current that he swims against the current. If the speed of the current is 3km/hr. , then what is the speed of the boy in still water ?

A) 9 km/hr

B) 13km/hr

C) 15km/hr

D) 22km/hr

E) 10km/hr

Answer is Option A

Solution:

Let the speed of boy in still water be x

km/hr

and the speed of current is given = 3 km/hr

Downstream speed = (x+3) km/hr

Upstream speed = (x-3) km/hr

Let time be t hours

(x+3)*t = 2 {(x-3)*t}

=> x = 9 km/hr

#### 11. A man can row 40 kmph in still water and the river is running at 10 kmph. If the man takes 2 hr to row to a place and back, how far is the place?

A) 38km

B) 37.5km

C) 40.75km

D) 41km

E) None

Answer is Option B

Solution:

Given u=40 , v=10

D= t[(u2-v2

)/2u]

=2*[(402-102

)/2*40]

=2*(1600-100)/80

2*1500/80==>37.5km

#### 12. A man rows to a place 60 km distant and come back in 35 hours. He finds that he can row 4 km with the stream in the same time as 3 km against the stream. Find the speed In still water and in stream:

A) 1.5, 2

B) 0.5, 2.5

C) 3.5, 0.5

D) 2, 2.5

E) None

Answer is Option C

Solution:

If he moves 4 km downstream in x hours.

Downstream speed=4/x

Upstream speed=3/x

Then 60/(4/x) + 60/(3/x)=35

60[(3x+4x)/12]=35

60*7x/12=35

5*7x=35==> x=1km.

Then Downstream speed=4km/hr ,

Upstream speed=3km/hr

U=(4+3)/2=7/2=3.5km/hr

V=(4-3)/2=1/2=0.5km/hr

#### 13. Speed of a boat in standing water is 12 kmph and the speed of the stream is 3 kmph. A man rows to a place at a distance of 6300 km and comes back to the starting point. The total time taken by him is:

A) 1120hrs

B) 1000hrs

C) 980hrs

D) 850hrs

E) None

Answer is Option A

Solution:

Downstream speed = (12 + 3) = 15 km/hr

Upstream speed = (12 – 3) = 9 km/hr

Total time taken =6300/15+6300/9

=420+700==>1120hrs.

#### 14. A boat takes 26 hours for travelling downstream from point A to point B and coming back to point C midway between Aand B. If the velocity of the stream is 4 km/hr and the speed of the boat in still  water is 10 km/hr, what is the distance between A and B?

A) 210km

B) 185km

C) 140km

D) 168km

E) None

Answer is Option D

Solution:

Downstream speed = 10+4 = 14

Upstream speed = 10-4 = 6

Now total time is 26 hours

If distance between A and B is d, then

distance BC = d/2

Now distance/speed = time, so

d/14 + (d/2)/6= 26

13d/84=26

Solve, d = 168 km

#### 15. At his usual rowing rate, Rahul can travel 12 miles downstream in a certain river in 6 hours less than it takes him to travel the same distance upstream. But if he could double his usual rowing rate for his 24-mile round trip, the downstream 12 miles would then take only one hour less than the upstream 12 miles. What is the speed of the current in miles per hour?

A) 2 2/3mph

B) 2mph

C) 1 1/4mph

D) 3mph

E) None

Answer is Option A)

Solution:

Let the speed of Rahul in still water be x

mph

and the speed of the current be y mph

Then, Speed upstream = (x – y) mph

Speed downstream = (x + y) mph

Distance = 12 miles

Time taken to travel upstream – Time taken

to travel downstream = 6 hours

12/(x-y) – 12/(x+y)=6

x2

=y2

+4y—1

Now he doubles his speed. i.e., his new

speed = 2x

Now, Speed upstream = (2x – y) mph

Speed downstream = (2x + y) mph

In this case, Time taken to travel upstream

– Time taken to travel downstream = 1

hour

12/(2x-y) – 12/(2x+y) = 1

4x2

=y2

+24y—2

From 1 and 2 we get

4y+y2

=(24y +y2

)/4

Y=8/3==> 2 2/3mph

#### 16. There is a road beside a river. Two friends started from a place A, moved to a temple situated at another place B and then returned to A again. One of them moves on a cycle at a speed of 6 km/hr, While the other sails on a boat at a speed of 8 km/hr. If the river flows at the speed of 6 km/hr, which of the two friends will return to place A first?

A) Cyclist

B) Sailor

C) Both come at same time

D) Any Other

E) None

Answer is Option A)

Solution:

Average speed of the cyclist =6 km/hr

Downstream speed=8+6=14 km/hr Upstream speed =8−6=2 km/hr

Therefore, average speed of the sailor

=2*14*2/(14+2)

=3.5km/hr

Average speed of the cyclist is more than

that of the sailor. Therefore, the cyclist will

return first.

#### 17. A boat running upstream takes 8 hours 48 minutes to cover a certain distance, while it takes 4 hours to cover the same distance running downstream. What is the ratio between the speed of the boat and speed of the water current respectively?

A) 5:4

B) 8:3

C) 7:6

D) 4:5

E) None

Answer is Option B)

Solution:

Let the man’s rate upstream be x kmph and

that downstream be y kmph.

Then, distance covered upstream in 8 hrs

48 min = Distance covered downstream in

4 hrs.

X*8 4/5 =4y

44/5x=4y

Y=11/5x.

Required ratio (y+x)/2=(y-x)/2

16x/10:6x/10

8:3

#### 18. A man takes thrice as long to row a  distance against the stream as to row the same distance in favour of the stream. The ratio of the speed of the boat (in still water) and the stream is:

A) 2:1

B) 3:2

C) 1:2

D) 2:3

E) None

Answer is Option A)

Solution:

Lets upstream be xkm/hr

Downstream be 3x km/hr

U: V=(3x+x)/2: (3x-x)/2

4x/2:2x/2

2:1

#### 19. A boat running downstream covers a distance of 40km in 4hrs and covering the same distance upstream in 8hrs. What is the speed of a boat in still water.

A) 6km/hr

B) 7km/hr

C) 7.5km/hr

D) 8.5km/hr

E) None

Answer is Option C)

Solution:

Downstream speed=40/4=10km/hr

Upstream speed=40/8=5km/hr

So speed of boat in still

water=(10+5)/2=15/2

=7.5km/hr

#### 20. A boat can travel 3.5km upstream in 14min. If the ratio of the speed of the boat in still water to the speed of the stream is 7:2. How much time will the boat take to cover 36km downstream ?

A) 65min

B) 80min

C) 75min

D) 70min

E) None

Answer  is Option B)

Solution:

Speed = 7x:2x

Downstream = 9x; upstream = 5x

Upstream speed = 3.5*60/14 = 15kmph

5x = 15

x = 3

Downstream = 9*3 = 27

Time taken for 36km = 36*60/27 = 80min

#### 21. Vimal can row a certain distance downstream in 14 hours and return the same distance in 21 hours. If the speed of the stream is 6 kmph, Find the speed of Vimal in the still water?

A) 21 kmph

B) 15 kmph

C) 30 kmph

D) 35 kmph

E) None of these

Answer is Option C)

Solution:

Speed of Vimal in still water = x

Downstream Speed = (x + 6)

Upstream Speed = (x – 6)

Downstream Distance = Upstream Distance

14(x + 6) = 21(x – 6)

2x + 12 = 3x – 18

x = 30 kmph.

#### 22. Rahul can row a certain distance downstream in 12 hour and return the same distance in 18 hour. If the speed of Rahul in still water is 12 kmph, find the speed of the

stream?

A) 2.1 kmph

B) 1.5 kmph

C) 4.4 kmph

D) 2.4 kmph

E) None of these

Answer is Option D)

Solution:

Let the speed of the stream be x kmph

Down stream = (12+x)

Up stream = (12−x)

suppose the distance traveled be y

y/(12+x) = 12 —(1)

y/(12−x)= 18 —-(2)

From eqn (1) and (2)

x= 2.4 kmph

#### 23. Anil can row 18 kmph in still water and he finds that it takes him twice as long to row up as to row down the river. Find the rate of streams?

A) 5 kmph

B) 6 kmph

C) 4 kmph

D) 3 kmph

E) None of these

Answer is Option B)

Solution:

Stream Speed = a kmph

Time Taken = x km

Downstream speed = (18 + a) kmph

Upstream speed = (18 – a) kmph

Time taken to travel downstream = 2 *

Time taken to travel upstream

(18 + a) / x = 2(18 + a) / x

18 + a = 36 – 2a

3a = 18

a = 6 kmph

OR USE FORMULA

Speed of boat = [tu+td]/[tu-td] * Speed of

stream

So 18 = [2x + x]/[2x – x] * Speed of stream

#### 24. Mr. Suresh can row to a place 48 km away and come back in 14 hours. He finds that he can row 4 km with the stream in the same time as 3 km against the stream. The rate of the stream is?

A) 1 kmph

B) 3 kmph

C) 4 kmph

D) 6 kmph

E) None of these

Option A)

Solution:

Downstream speed = 4/x kmph

upstream speed = 3/x kmph

48/(4/x) + 48/(3/x) = 14

Solving we get x = 1/2 kmph

So, Speed of downstream = 8 kmph, Speed

of upstream = 6 kmph

Stream Speed = 1/2(8 – 6) kmph = 1 kmph

#### 25. Mr.Ramesh’s speed with the current is 20 kmph and the speed of the current is 5 kmph. Ramesh’s speed against the current is?

A) 15 kmph

B) 19 kmph

C) 17 kmph

D) 10 kmph

E) None of these

Answer is Option D)

Solution:

Ramesh’s speed with the current = 20

kmph

=> Ramesh’s speed + speed of the current

= 20 kmph

Speed of the current = 5 kmph

Speed of Ramesh = 20 – 5 = 15 kmph

Ramesh’s speed against the current = speed

of Ramesh – speed of the current = 15 – 5

= 10 kmph

#### 26. Ravi can row 12 kmph in still water when the river is running at 6 kmph it takes him 1 hour to row to a place and to come back. How far is the place?

A) 5.5 km

B) 4.5 km

C) 8.2 km

D) 4.2 km

E) None of these

Answer is Option B)

Solution:

Downstream Speed = 18 kmph

Upstream Speed = 6 kmph

Distance = x

x/18 + x/6 = 1

18x + 6x = 108

24x = 108

x = 4.5 km

OR USE FORMULA:

Distance = time [B2 – R2

]/2*B

So distance = 1 * [122 – 62

]/2*12

Distance = 108/24 = 4.5 km

#### 27. The different between downstream speed and upstream speed is 2 kmph and the total time taken during upstream and downstream is 2 hours. What is the upstream speed, if the downstream and upstream distance are 2 km each?

A) 5.2 kmph

B) 3.7 kmph

C) 2.8 kmph

D) 1.4 kmph

E) None of these

Answer is Option D)

Solution:

2/x + 2/(x+2) = 2.

x2 – 2 = 0

x = 1.414kmph

#### 28. Rani can row 8 kmph in still water. If the river is running at 4 kmph it takes 90 minutes to row to a place and back. How far is the place?

A) 4.5 km

B) 8.2 km

C) 4.2 km

D) 3.5 km

E) None of these

Answer is Option A)

Solution:

Speed in still water = 8 kmph

Speed of the stream = 4 kmph

Upstream Speed = (8-4) = 4 kmph

Downstream Speed = (8+4) = 12 kmph

Total time = 90 minutes = 90/60 = 3/2 hrs

Let x is the distance

x/12 + x/4 = 3/2

x = 4.5 km

#### 29. Sumi can swim 6 kmph in still water. If the velocity of the stream be 2 kmph, the time taken by her to swim to a place 24 km upstream and back, is?

A) 6 hours

B) 5 hours

C) 4 hours

D) 8 hours

E) 9 hours

Answer is Option E)

Solution:

Upstream speed = speed of man – speed of

stream=6 – 2 = 4

Downstream speed = speed of man + speed

of stream=6 + 2=8

Time taken to go upstream =

distance/speed = 24/4 =6 hour

Time taken to go downstream =

distance/speed =24/8 = 3 hour

Total time =6+3 = 9 hour

#### 30. Raghu can row 96 km downstream in 8 hours. If the speed of the current is 3kmph, then find in what time will be able to cover 12 km upstream?

A) 6 hours

B) 5 hours

C) 4 hours

D) 8 hours

E) 2 hours

Answer is Option E)

Solution:

Downstream speed = 96/8 = 12 kmph

Speed of current = 3 kmph

Speed of kamal in still water = 12-3 = 9

kmph

Upstream speed = 9-3 = 6 kmph

Time taken to cover 12 km upstream 12/6 =

2 hours

#### 31.A boat can cover 21 km in the direction of current and 15 km against the current in 3 hours each. Find the speed of current.

A) 4.5 km/hr

B) 2.5 km/hr

C) 3 km/hr

D) 1 km/hr

E) 6 km/hr

Answer is Option D)

Solution:

Downstream speed = 21/3 = 7 km/hr

Upstream speed = 15/3 = 5 km/hr

So speed of current = 1/2 * (7-5)

#### 32. A boat in a river with a speed of stream as 6 km/hr can travel 7 km upstream and back in 4 hours. What is the speed of the boat in still water?

A) 10 km/hr

B) 8 km/hr

C) 11 km/hr

D) 12 km/hr

E) 15 km/hr

Answer is Option B)

Solution:

Let speed of boat is x km/hr

So

7/(x+6) + 7/(x-6) = 4

Solve, x = 8 km/hr [ignore the negative root

because speed cannot be negative]

#### 33. A boat can cover 40 km upstream and 60 km downstream together in 13 hours.Also it can cover 50 km upstream and 72 km downstream together in 16 hours. What is the speed of the boat in still water?

A) 5.5 km/hr

B) 6.5 km/hr

C) 8.5 km/hr

D) 3.5 km/hr

E) None of these

Answer is Option C)

Solution:

Upstream speed in both cases is 40 and 50. Ratio

is 40 : 50 = 4 : 5. So let times in both cases be 4x

and 5x

Downstream speed in both cases is 60 and 72

resp. Ratio is 60 : 72 = 5 : 6. So let times in both

cases be 5y and 6y

So 4x + 5y = 13

and 5x + 6y = 16

Solve both, x = 2, y = 1

So upstream speed is = 40/4x = 5 km/hr

And downstream = 60/5y = 12 km/hr

So speed of boat is 1/2 * (5+12)

#### 34. A boat can row to a place 56 km away and come back in 22 hours. The time to row 21 km with the stream is same as the time to row 12 km against the stream. Find the speed of boat in still water.

A) 1.5 kmph

B) 3.5 kmph

C) 5.5 kmph

D) 7.5 kmph

E) None of these

Answer is Option C)

Solution:

Downstream speed = 21/x km/hr

Upstream speed = 12/x km/hr

56/(21/x) + 56/(12/x) = 22

Solve, x = 3 km/hr

So, downstream speed = 7 km/hr, upstream

speed = 4 km/hr

Speed of boat = 1/2 * (7 + 4) km/hr

#### 35. A boat travels downstream from point A to B and comes back to point C half distance between A and B in 18 hours. If the speed of the boat is still water is 7 km/hr and distance AB = 80 km, then find the downstream speed.

A) 15 km/hr

B) 18 km/hr

C) 12 km/hr

D) 10 km/hr

E) 6 km/r

Answer is Option D)

Solution:

A to B is 80, so B to is 80/2 = 40 km

Let speed of current = x km/hr

So 80/(7+x) + 40/(7-x) = 18

Solve, x = 3 km/hr

So downstream speed = 7 + 3 = 10 km/hr

#### 36. A boat can cover 20 km upstream and 32 km downstream together in 3 hours. Also it can cover 40 km upstream and 48 km downstream together in 5 and half hours. What is the speed of the current?

A) 13 km/hr

B) 8 km/hr

C) 7 km/hr

D) 11 km/hr

E) 16 km/hr

Answer is Option D)

Solution:

Upstream speed in both cases is 20 and 20 resp.

Ratio is 20 : 40 = 1 : 2. So let times in both cases

be x and 2x

Downstream speed in both cases is 32 and 48

resp. Ratio is 32 : 48 = 2 : 3. So let times in both

cases be 2y and 3y

So x + 2y = 3

and 2x + 3y = 5 1/2

Solve both, x = 2, y = 0.5

So upstream speed is = 20/x = 10 km/hr

And downstream = 32/2y = 32 km/hr

So speed of boat is 1/2 * (32-10)

#### 37. Speed of boat in still water is 14 km/hr while the speed of current is 10 km/hr. If it takes a total of 7 hours to row to a place and come back, then how far is the place?

A) 30 km

B) 18 km

C) 24 km

D) 32 km

E) None of these

Answer is Option C)

Solution:

USE FORMULA:

Distance = total time * [B2 – R2

]/2*B

So distance = 7 * [142 – 102

]/2*14

Distance = 24 km

#### 38. A man can row a certain distance downstream in 4 hours and return the same distance in 8 hours. If the speed of current is 16 km/hr, find the speed of man in still water.

A) 47 km/hr

B) 48 km/hr

C) 42 km/hr

D) 50 km/hr

E) None of these

Answer is Option B)

Solution:

Use formula:

B = [tu + td] / [tu – td] * R

B = [8+4] / [8-4] * 16

B = 48 km/hr

#### 38. There are 3 point A, B and C in a straight line such that point B is equidistant from points A and C. A boat can travel from point A to C downstream in 12 hours and from B to A upstream in 8 hours. Find the ratio of boat in still water to speed of stream.

A) 9 : 2

B) 8 : 3

C) 7 : 1

D) 4 : 1

E) 7 : 3

Answer is Option C)

Solution:

Let speed in still water = x km/hr, of current = y

km/hr

Downstream speed = (x+y) km/hr

Upstream speed = (x – y) km/hr

Let AC = 2p km. So AB = BC = p km.

So

2p/(x+y) = 12

And

p/(x-y) = 8

Divide both equations, and solve

x/y = 7/1

#### 39. A boat can row 18 km downstream and back in 8 hours. If the speed of boat is increased to twice its previous speed, it can row same distance downstream and back in 3.2 hours. Find the speed of boat in still water.

A) 9 km/hr

B) 5 km/hr

C) 4 km/hr

D) 8 km/hr

E) 6 km/hr

Answer is Option E)

Solution:

Let speed of boat = x km/hr and that of stream =

y km/hr

So

18/(x+y) + 18/(x-y) = 8

when speed of boat becomes 2x km/hr:

18/(2x+y) + 18/(2x-y) = 3.2

Solve, x= 6 km/hr

#### 40. A boat can cover 25 km upstream and 42 km downstream together in 7 hours. Also it can cover 30 km upstream and 63 km downstream together in 9 hours. What is the speed of the boat in still water?

A) 13 km/hr

B) 8 km/hr

C) 7 km/hr

D) 11 km/hr

E) 16 km/hr

Answer is Option A)

Solution:

Upstream speed in both cases is 25 and 30

resp. Ratio is 25 : 30 = 5 : 6. So let times in

both cases be 5x and 6x

Downstream speed in both cases is 42 and

63 resp. Ratio is 42 : 63 = 2 : 3. So let

times in both cases be 2y and 3y

So 5x + 2y = 7

and 6x + 3y = 9

Solve both, x = 1, y = 1

So upstream speed is = 25/5x = 5 km/hr

And downstream = 42/2y = 21 km/hr

So speed of boat is 1/2 * (5+21)

#### 42. A man rows to a certain place and comes back, but by mistake he covers 1/3rd more distance while coming back. The total time for this journey is 10 hours. The ratio of speed of boat to that of stream is 2 : 1. If the difference between upstream and downstream speed is 12km/hr, then how much time will the man take to reach to starting point from his present position?

A) 35 minutes

B) 45 minutes

C) 60 minutes

D) 40 minutes

E) 55 minutes

Answer is Option D)

Solution:

Speed of boat and stream – 2x and x

respectively. So downstream speed = 2x+x

= 3x, and upstream speed = 2x-x = x

Let total distance between points is d km

So he covered d km downstream, and while coming back i.e. upstream he covers d + 1/3 *d = 4d/3 km

Total time for this journey is 10 hrs. So

d/3x + (4d/3)/x = 10

Solve, d = 6x

Now also given, that (2x+x) – (2x-x) = 12

Solve, x = 6

So d = 36 km

So to come to original point, he will have

to cover 1/3 * 36 = 12 km

And with speed 3x = 18

km/hr(downstream)

So time is 12/18 * 60 = 40 minutes

#### 43. A man can row at a speed of 15 km/hr in still water to a certain upstream point and back to the starting point in a river which flows at 9 km/hr. Find his average speed for total journey.

A) 10.4 km/hr

B) 8.4 km/hr

C) 9.1 km/hr

D) 5.2 km/hr

E) 9.6 km/hr

Answer is Option E)

Solution:

When the distance is same, then average

speed throughout journey would be:

Speed downstream * Speed upstream/speed

in still water.

So here average speed = (15+9)*(15-9)/15

= 9.6 km/hr

#### 44. A boat takes 5 hours for travelling downstream from point A to point B and coming back to point C at 3/4th of total distance between A and B from point B. If the velocity of the stream is 3 kmph and the speed of the boat in still water is 9 kmph, what is the distance between A and B?

A) 24 km

B) 32 km

C) 27 km

D) 21 km

E) 34 km

Answer is Option A)

Solution:

Let total distance from A to B= d km, So

CB = 3d/4 km

So

d/(9+3) + (3d/4)/(9-3) = 5

Solve, d = 24 km

#### 45. At its usual rowing rate, a boat can travel 18 km downstream in 4 hours less than it takes to travel the same distance upstream. But if he the usual rowing rate for his 28-km round trip was 2/3rd, the downstream 14 km would then take 12 hours less than the upstream 14 km. What Is the speed of the current?

A) 1.5 km/h

B) 3 km/h

C) 2 km/h

D) 3.5 km/h

E) 4 km/hr

Answer is Option B)

Solution:

Let speed of boat = x km/hr, and of current

= y km/hr

So

18/(x-y) = 18/(x+y) + 4

Gives x2

= 9y + y2……..(1)

Now when speed of boat is 2x/3

14/(2x/3 -y) = 14/(2x/3 +y) + 12

42/(2x-3y) = 42/(2x+3y) + 12

Gives 4x2

= 21y + 9y2…………(2)

From (1), put value of x2

in (2) and solve

Solving, x = 6, y = 3

#### 46. A boat can row to a place 120 km away and come back in 25 hours. The time to row 24 km with the stream is same as the time to row 16 km against the stream. Find the speed of current.

A) 1.5 km/h

B) 3 km/h

C) 2 km/h

D) 3.5 km/h

E) 4 km/hr

Answer is Option C)

Solution:

Downstream speed = 24/x km/hr

Upstream speed = 16/x km/hr

120/(24/x) + 120/(16/x) = 25

Solve, x = 2 km/hr

So, downstream speed = 12 km/hr,

upstream speed = 8 km/hr

Speed of current = 1/2 * (12 – 8) km/hr

#### 47. A boatman can row 4 Km against the stream in 20 minutes and return in 24 minutes. Find the speed of boatman in still water.

A) 10 km/hr

B) 8 km/hr

C) 15 km/hr

D) 12 km/hr

E) 11 km/hr

Answer is Option E)

Solution:

Upstream speed = 4/20 * 60 = 12 km/hr

Downstream speed = 4/24 * 60 = 10 km/hr

Speed of boatman = 1/2 (12+10) = 11

km/hr

#### 48. A man can row a certain distance downstream in 3 hours and return the same distance in 9 hours. If the speed of current is 18 km/hr, find the speed of man in still water.

A) 47 km/hr

B) 48 km/hr

C) 42 km/hr

D) 50 km/hr

E) 36 km/hr

Answer is Option E)

Solution:

Use formula:

B = [tu + td] / [tu – td] * R

B = [9+3] / [9-3] * 18

B = 36 km/hr

#### 49. Four times the downstream speed is 8 more than 15 times the upstream speed. If the difference between downstream and upstream speed is 24 km/hr, then what is  the ratio of speed in still water to the speed of the current?

A) 9 : 2

B) 5 : 3

C) 7 : 1

D) 4 : 1

E) 7 : 3

Option B)

Solution:

Let speed in still water = x km/hr, of

current = y km/hr

So

4 (x+y) = 15(x-y) + 8

Solve, 11x – 19y + 8 = 0…….(1)

Also (x+y) – (x-y) = 24

So y = 12

Put in (1). x = 20

So x/y = 20/12 = 5/3

50. A boat can cover 14 km upstream and 21 km downstream together in 3 hours. Also it can cover 21 km upstream and 42 km downstream together in 5 hours. What is the speed of current?

A) 13 km/hr

B) 8 km/hr

C) 7 km/hr

D) 11 km/hr

E) 16 km/hr

Answer is Option C)

Solution:

Upstream speed in both cases is 14 and 21

resp. Ratio is 14 : 21 = 2 : 3. So let times in

both cases be 2x and 3x

Downstream speed in both cases is 21 and

42 resp. Ratio is 21 : 42 = 1 : 2. So let

times in both cases be y and 2y

So 2x + y = 3

and 3x + 2y = 5

Solve both, x = 1, y = 1

So upstream speed is = 14/2x = 7 km/hr

And downstream = 21/y = 21 km/hr

So speed of current is 1/2 * (21-7)

51. The speed of a Boat in standing water is 10km/hr. It traveled Down Stream from point A to B in certain time. After reaching B the Boat is powered by Engine then Boat started to return from Point B to A. The time taken for Forward journey and Backward journey are same. Then what is the speed of the stream?

1. 2 Km/hr

2. 3 Km/hr

3. 4 Km/hr

4. 5 Km/hr

5. Cannot be determined

Answer – 5. Cannot be determined

Explanation :

S+R = D/t ; S-R+x = D/t

S+R = S-R+x

R =x/2

52. A Boat going upstream takes 8 hours 24 minutes to cover a certain distance, while it takes 5 hours to cover 5/7 of the same distance running downstream. Then what is the ratio of the speed of boat to speed of water current?

1. 6:5

2. 11:5

3. 11:6

4. 11:1

5. 11:10