Question
A boat travels 150 km downstream in 6 hours. The
difference between its downstream speed and upstream speed is 3 km/h. What is the ratio of the boat's speed in still water to the speed of the stream?Solution
ATQ;
Downstream speed = 150 ÷ 6 = 25 km/h
Let boat speed in still water = b, stream speed = s
Downstream = b + s = 25
Upstream = b – s
Difference between downstream and upstream = (b + s) – (b – s) = 2s = 3
Hence s = 1.5
Then b = 25 – s = 23.5
Required ratio = 23.5 : 1.5 = 47 : 3
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