Question

A man swims downstream a distance of 15 km in 1 hour. If the speed of the current is 5 km/hour, the time taken by the man to swim the same distance upstream is

• A. 1 hour 30 minutes
• B. 45 minutes
• C. 2 hours 30 minutes
• D. 3 hours

Answer 1

Answer:

D. 3 hours

Let the speed of man in still water be x kmph.

$\frac{15}{x+5}=1$

x + 5 = 15

x = 10 kmph

Time taken in swimming upstream $=\frac{15}{10-5}=\frac{15}{5}=3 hours$