Boats and Streams Quiz Set 015


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Question 1

A boat travels a downstream distance of 28 km in 2 hours, and an upstream distance of 56 km in 7 hours. What is the speed of the stream?

 A

3 kmph.

 B

4 kmph.

 C

2 kmph.

 D

6 kmph.

Soln.
Ans: a

The downstream speed = $28/2$ = 14 km/h, and the upstream speed = $56/7$ = 8 km/h. By the shortcut method, the speed of the stream is half of the difference between the downstream and upstream speeds of the boat. So the required speed = ${14 - 8}/2$ = 3 km/h.


Question 2

A boat travels a downstream distance of 60 km in 5 hours, and an upstream distance of 30 km in 5 hours. What is the speed of the stream?

 A

3 kmph.

 B

4 kmph.

 C

2 kmph.

 D

6 kmph.

Soln.
Ans: a

The downstream speed = $60/5$ = 12 km/h, and the upstream speed = $30/5$ = 6 km/h. By the shortcut method, the speed of the stream is half of the difference between the downstream and upstream speeds of the boat. So the required speed = ${12 - 6}/2$ = 3 km/h.


Question 3

If the speed of a boat in the direction of the stream current is 24 km/h, and the speed of the current is 10 km/h, what would be the speed of the boat against the current?

 A

4 km/h.

 B

5 km/h.

 C

3 km/h.

 D

7 km/h.

Soln.
Ans: a

Speed of the boat in still water is the difference between its downstream speed and the speed of the stream, which is 24 - 10 = 14 km/h. Hence, the speed of the boat against the current is 14 - 10 = 4 km/h.


Question 4

A boat can travel 252 km downstream in 18 hours. If it covers the same distance upstream in 42 hours, what is the rate of flow of the stream?

 A

4 kmph.

 B

5 kmph.

 C

3 kmph.

 D

7 kmph.

Soln.
Ans: a

The downstream speed = $252/18$ = 14 km/h, and the upstream speed = $252/42$ = 6 km/h. By the shortcut method, the speed of the stream is half of the difference between the downstream and upstream speeds of the boat. So the required speed = ${14 - 6}/2$ = 4 km/h.


Question 5

A boat has a downstream speed of 16 km/h and an upstream speed of 6 km/h. What is the speed of the stream?

 A

5 kmph.

 B

6 kmph.

 C

4 kmph.

 D

8 kmph.

Soln.
Ans: a

By the shortcut method, the speed of the stream is half of the difference between the downstream and upstream speeds of the boat. So the required speed = ${16 - 6}/2$ = 5 km/h.


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This Blog Post/Article "Boats and Streams Quiz Set 015" by Parveen (Hoven) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Updated on 2020-02-07. Published on: 2016-05-06

Posted by Parveen(Hoven),
Aptitude Trainer


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