Multiple choice

Ravi goes by a boat running upstream and takes 6 hours 54 minutes to reach a place P, while it takes 3 hours to cover the same distance running downstream. What is the ratio between the speed of the boat and speed of the current respectively?

  1. 33 : 13

  2. 23 : 13

  3. 13 : 23

  4. 33 : 12

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

Upstream time = 6h 54m = 6.9h. Downstream time = 3h. Let distance be D. Upstream speed (u-v) = D/6.9. Downstream speed (u+v) = D/3. u = (D/3 + D/6.9)/2 = D(1/6 + 1/13.8) = D(2.3+1)/13.8 = 3.3D/13.8. v = (D/3 - D/6.9)/2 = D(2.3-1)/13.8 = 1.3D/13.8. Ratio u:v = 3.3:1.3 = 33:13.

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