Question
A boat can travel 7.2 km upstream in 18 min. If the
ratio of the speed of the boat in still water to the speed of the stream is 7:1. How much time will the boat take to cover 17.6 km downstream ?Solution
Speed = 7x : 1x
Downstream = 8x; upstream = 6x
Upstream speed = 7.2 x (60/18) = 24 kmph
6x = 24
x = 4
Downstream = 8 x 4 = 32
Time taken for 17.6 km = 17.6 x (60/32) = 33 min
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