Question

A boat can travel 14.4 km downstream in 32 min.if the speed of current is 3 kmph,how much time the will the boat take to travel 84 km upstream?

Answer 1

Take Time = distance /speed
Let the speed of boat in still water : X km/h
Streams speed = 3 km/h

Downstream

14.4/(X + 3) = 32/60
32(X + 3) = (60 x 14.4)
32X + 96 = 864
32X = 864 - 96
32X = 7 68
X = 768 / 32
X = 384 / 16
X = 192 / 8
X = 96 / 4
X = 24
Therefore the speed of boat in still water = 24 km/h

Upstream

84 / (24 - 3)
= 84 / 21
= 4
Time taken during upstream 4 hours.

Answer 2

Refer to the attachment