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A boat takes 9 h to travel a distance upstream and takes 3 h to travel the Same distance downstream. If the speed of the boat in still water is 4 km/h. then what is the velocity of the stream?

A) 4 km/h
B) 3 km/h
C) 6 km/h
D) 2 km/h

Correct Answer:




D) 2 km/h

Description for Correct answer:

Let velocity of the stream be x km/h.

Therefore, Velocity of the boat downstream

= (4 + x) km/h

and velocity of the boat upstream

= (4 - x) km/h

According to the question,

\( \Large 3 \left(4+x\right) = 9 \left(4-x\right) \)

=> \( \Large 12 + 3x = 36 - 9x \)

=> 12x = 24

Therefore, x =2 km/h

Part of solved Boat and Stream questions and answers : >> Aptitude >> Boat and Stream

Comments

Similar Questions

1). A boat running upstream distance of 10 km in 30 min and while running downstream, it covers the same distance in 25 min. What is the speed of the river current (in km/h)?

A). 20

B). 2.2

C). 2

D). Couldn't be determined

2). A man can row at 10 km/h in still water. If he takes total 5 h to go to a place 24 km away and return, then the speed of the water current is

A). 2 km/h

B). 3 km/h

C). \( \Large \frac{1}{2} \) km/h

D). 1 km/h

3). A steamer goes downstream from one port to another in 4 h. It covers the same distance upstream in 5 h. If the speed of the stream is 2 km/h, then find the distance between the two ports.

A). 50 km

B). 60 km

C). 70 km

D). 80 km

4). A man can row \( \Large 7\frac{1}{2} \) km/h in still water. If in a river running at 1.5 km/h, it takes him 50 min to row to a place and back, how far off is the place?

A). 3 km

B). 4 km

C). 1 km

D). 2 km

5). Ashutosh can row 24 km/h in still water. It takes him twice as long to row up as to row down the river. Find the rate of stream.

A). 4 km/h

B). 18 km/h

C). 8 km/h

D). 15 km/h

6). A boat goes 12 km in 1 h in still water. It takes thrice time in covering the same distance against the current. Find the speed of the current.

A). 8 km/h

B). 12 km/h

C). 6 km/h

D). 7 km/h

7). A boatman takes twice as long to row a distance against the stream as to row the same distance with the stream. Find the ratio of speeds of the boat in still water and the stream.

A). 2 : 1

B). 3 : 1

C). 1 : 2

D). 1 : 3

8). A boat running upstream takes 528 min to cover a certain distance, while it takes 240 min 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). 2 : 1

B). 3 : 2

C). 8 : 3

D). Couldn't be determined

9). A river is flowing with a steady speed of 4 km/h. One rows his boat downstream in the river and then returns by rowing upstream in the same river. When he returns to the starting point, the total distance covered by him is 42 km. If the return journey takes 2 h more than his outward journey, then the speed of his rowing in still water must be

A). 12 km/h

B). 10 km/h

C). 9 km/h

D). 8 km/h

10). The ratio of speeds of a motorboat to that of the current of water is 36 : 5. The motorboat goes along with the current in 5 h 10 min. Find the time to come back of motorboat.

A). 5 h 50 min

B). 6 h

C). 6 h 50 min

D). 12 h 10 min