Multiple choice

A person swims a distance of 28 km. in the direction of stream in 5 hours and a distance of 13 km. in 5 hours against the stream. What is the speed of the stream?

  1. 2 km./hr.

  2. 1.5 km./hr.

  3. 2.5 km./hr.

  4. 1.8 km./hr.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Downstream speed = 28/5 = 5.6 km/h. Upstream speed = 13/5 = 2.6 km/h. Stream speed = (downstream - upstream)/2 = (5.6 - 2.6)/2 = 3/2 = 1.5 km/h. This is a standard formula: speed of current = (speed with stream - speed against stream) / 2.

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