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GMAT prep boat stream problem
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subhasis8877
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Time = Distance / Speed
Let upstream's time taken is 90 / v-3 + 1/2 [Since upstream journey took half an hour longer than downstream]
Let downstream's time taken is 90 / v+3
Equate the time of both upstream and downstream,
90 / v-3 + 1/2 = 90 / v+3
Solving for V, you get V as 33.
We are asked to find the total time taken for downstream journey. So, t = 90 / v + 3 = 90 / 36 = 15/6 = 2.5 hours
Let upstream's time taken is 90 / v-3 + 1/2 [Since upstream journey took half an hour longer than downstream]
Let downstream's time taken is 90 / v+3
Equate the time of both upstream and downstream,
90 / v-3 + 1/2 = 90 / v+3
Solving for V, you get V as 33.
We are asked to find the total time taken for downstream journey. So, t = 90 / v + 3 = 90 / 36 = 15/6 = 2.5 hours
