Multiple choice

A man rows to a place 60 km distance 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:

  1. 1.5, 2

  2. 0.5, 2.5

  3. 3.5, 0.5

  4. 2, 2.5

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Downstream: 4 km in same time as 3 km upstream. Let boat speed = b, stream speed = s. Then 4/(b+s) = 3/(b-s). Cross-multiply: 4b - 4s = 3b + 3s, so b = 7s. Total time: 60/(b+s) + 60/(b-s) = 35. Substituting b = 7s: 60/8s + 60/6s = 35. So 7.5/s + 10/s = 35, s = 0.5, b = 3.5.

Keep practicing — related questions