Boats and Streams | Arithmetic aptitude | Discussion Page | Question 1048

1)

A man swims downstream 40 km in 4 hours and upstream 24 km in 3 hours. Find his speed in still water.

A) 9 km/hr

B) 10 km/hr

C) 11 km/hr

D) 12 km/hr

E) 13 km/hr

Answer:

Option A

Explanation:

Downstream speed $=\frac{40}{4}$ $=10$ km/hr

Upstream speed $=\frac{24}{3}$ $=8$ km/hr

Speed in still water $=\frac{1}{2}(10 + 8)$ = 9 km/hr.