Multiple choice

If the speed of boat upstream is 20 km/h and speed of boat downstream is 30 km/h, then find the speed of river ?

  1. 10 km/h

  2. 8 km/h

  3. 9 km/h

  4. 5 km/h

  5. 7 km/h
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D Correct answer
Explanation

Speed of boat (b) + speed of river (r) = 30. b - r = 20. Subtracting: 2r = 10, so r = 5 km/h.

AI explanation

Using the formula for the speed of the stream, we calculate one half of the difference between the downstream speed and the upstream speed. This gives one half of (30 minus 20), which equals one half of 10. The speed of the river is 5 km/h.

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