Question

A river is flowing from west to east at a speed of 5 meters per minute. A man on the south bank of the river, capable of swimming at 10 meters per minute in still water, wants to swim across the river in the shortest time. He should swim in a direction:

• A. due north
• B. 30 east of north
• C. 30 north of west
• D. 60 east of north.

Answer 1

The correct option is A due north

In order to swim across the river in the shortest time, the man should swim straight due north. This is because the velocity of the river is west to east and there is no component in north-south. So, it will not affect the man's time in order to swim to the other bank.