Multiple choice

A boat travels upstream from P to Q and downstream from Q to P in 3 hours. If the speed of the boat in still water in 9 km/hr and the speed of the stream is 3 km/hr, then what is the distance from P to Q?

  1. 8 Km

  2. 12 Km

  3. 15 Km

  4. 24 Km
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Upstream speed = 9 - 3 = 6 km/hr, downstream speed = 9 + 3 = 12 km/hr. Time = d/6 + d/12 = 3 hours. Solving: (2d + d)/12 = 3, so d = 12 km. Distance PQ is 12 km, but the question asks total distance (round trip) = 24 km.

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