Question

A boat covers 45 km upstream and 68 km downstream in 9 hrs . While the boat covers 72 km upstream and 51 km downstream in 11 hrs. Speed of boat in still water is?

Answer 1

Let downstream speed be D and Upstream speed be U. Then

(48/D + 72/U) = 12 -------- (1)

and

(48/D + 72/U) = 13 ------------ (2) On solving the eqn (1) and (2), we get

D = 12 kmph and

U = 8 kmph

Thus, speed of the current = (D-U)/2 = 4/2 = 2 kmph.