Multiple choice

The speed of a motorboat itself is 20 km/hr and the rate of flow of the river is 4 km/hr. Moving along the stream, the boat goes 120 km. What distance will the boat cover during the same time going against the stream?

  1. 100 km

  2. 80 km

  3. 40 km

  4. 120 km

  5. 60 km
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Downstream speed = 20+4 = 24 km/hr. Time taken for 120 km = 120/24 = 5 hours. Upstream speed = 20-4 = 16 km/hr. Distance covered in 5 hours = 16 * 5 = 80 km.

AI explanation

The downstream speed is calculated as 20 plus 4, giving 24 km/hr, and the upstream speed is 20 minus 4, giving 16 km/hr. Using the Time formula, the time taken to travel 120 km downstream is 120 divided by 24, which equals 5 hours. Using the Distance formula for the return trip, the distance covered upstream in the same time is 16 multiplied by 5. The distance covered going against the stream is 80 km.

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