Multiple choice

Directions: Select the correct alternative from the given choices. lf it takes 50% more time to row a boat upstream over a certain distance than what it takes to row the boat downstream over the same distance, then how many times the speed of the stream is the speed of the boat upstream?

  1. 4

  2. 1

  3. 1.5

  4. 5
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A Correct answer
Explanation

If the downstream time is t, the upstream time is 1.5t, so the upstream speed is 2/3 of the downstream speed. Let the boat speed in still water be b and stream speed be s. Solving b - s = 2/3(b + s) gives b = 5s, so the upstream speed b - s is 4 times the stream speed.

AI explanation

Because speed and time are inversely proportional for a constant distance, the ratio of upstream time to downstream time is 1.5 to 1. This means the ratio of upstream speed to downstream speed is 1 to 1.5, which equals 2 to 3. By solving the speed equations, upstream speed is twice the speed of the stream.

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