Multiple choice

A boat running downstream covers a distance of 10 km in 2 hours. If the speed of the stream is 1.5 kmph, what is the speed of the boat in still water?

  1. 2.5 kmph

  2. 4.5 kmph

  3. 3.5 kmph

  4. Cannot be determined

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Downstream speed = 10 km / 2 hr = 5 kmph. Downstream speed = boat speed + stream speed. 5 = boat speed + 1.5, so boat speed = 3.5 kmph.

AI explanation

Using the formula speed equals distance divided by time, the downstream speed of the boat is 10 km divided by 2 hours, which equals 5 kmph. Since the downstream speed equals the speed of the boat in still water plus the speed of the stream, we set up the equation 5 = boat speed + 1.5. Solving this gives the speed of the boat in still water as 3.5 kmph.

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