A boat P travels 80 km upstream from point A to point B in 10 hours and downstream from point B to point A in 5 hours. Another boat Q can travel from point A to a point C 60 km upstream in 5 hours. What is the speed of the boat Q in still water?
Explanation:
Let P km/hr be the speed of boat P, and Q km/hr be the speed of boat Q.
Let s km/hr be the rate of flow of stream.
We have,
P - s = 80/10 = 8 and P + s = 80/5 = 16
Solving, we get P = 12 and s = 4
Again, Q - s = 60/5 = 12
Thus, s = 4 and Q = 16.
Thus, speed of boat Q in still water is 16 km/hr.
Hence, option (b).
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