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.