Question

A boy swims 200 m in still water and then returns back to the point of start in total 10 minutes. Find the speed of his swim in kmph.

• A. 0.66 kmph
• B. 2.1 kmph
• C. 1.5 kmph
• D. 2.4 kmph

Answer 1

The correct option is D 2.4 kmph

A boy swims 200 m in still water and then returns back to the starting point in total 10 minutes
Distance = 200 m + 200 m = 400 m
Time = 10 minutes = 600 seconds
speed = $\frac{400}{600}=\frac{4}{6}=\frac{2}{3}$ m/s
Converting m/s to km/hr
speed = $\frac{2}{3}\times \frac{18}{5}=\frac{36}{15}=2.4$ kmph