A boat travels upstream from A to B and back from B to A in 5 hours The speed of the boat in still w...........

Quantitative Aptitiude (CLAT) Boats and Streams

A boat travels upstream from A to B and back from B to A in 5 hours. The speed of the boat in still water is 8 km/hour and the speed of the current is 4 km/hour. Then, the distance from A to B is:

9 kms

10 kms.

12 kms.

15 kms.

Explanation:

Upstream speed (US) = 9 - 5 = 4 kmph
Downstream speed (DS) = 9 + 5 = 14 kmph
Average speed = 2 x 4 x 14/(4 + 18) = 6 kmph(approx.)
=> Total distance = 6 x 5 = 30 km
Distance between A & B is 30/2 = 15 km.