Question

The ratio of the speed of boat A, boat B and stream is 15 : 14 : 10, If the difference between the speed of boat A and boat B is 2 kmph, then what is the difference between time taken by boat A to cover 150 km along the stream and the time taken by boat B to cover 120 km against stream?
1. 16
2. 12
3. 10
4. 14
5. None of these.

Answer 1

Correct Answer - Option 2 : 12

Given:

Ratio of speed of boat A, boat B and stream = 15 : 14 : 10

Speed of boat A – Speed of boat B = 2 kmph

Concept used:

Time = Distance/Speed

Calculation:

Difference of boat A and boat B = 15 – 14 = 1

1 unit equal to 2 kmph

So, speed of boat A is 30 kmph

speed of boat B is 28 kmph

speed of stream is 20 kmph

Time taken by boat A = [150/(30 + 20)]

⇒ 150/50

⇒ 3 hours

Time taken by boat B = [120/(28 - 20)]

⇒ 120/8

⇒ 15 hours

Diffrence between time taken by boat A and boat B

⇒ 15 – 3

⇒ 12 hours

∴ The difference between time taken by boat A and boat B is 12 hours.