Multiple choice

A man can row at the speed of 8 km/hr in still water. When the speed of the current in the river is 1.6 km/hr, it takes him 1 hour to row to a place and return back. How far is the place?

  1. 9.6 km

  2. 6.4 km

  3. 3.91 km

  4. 3.2 km

  5. 3.84 km

Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Man's rate while going downstream = (8 + 1.6) = 9.6 km/hr

Man's rate going upstream = (8 - 1.6) = 6.4 km/hr

Let the required distance be x km.

Then, (x/9.6) + (x/6.4) = 1

6.4x + 9.6x = 6.4 * 9.6

16x = 6.4 * 9.6

x = (6.4 * 9.6)/16

x = 6.4 * 0.6

x = 3.84 km

It is the correct answer.