A man can swim along the stream at 3 km/h and against the stream at 2 km/hr. How long will he take to swim 7 km in still water?

2 h 48 m

Let Man's Velocity in Still water be "v"

Let Velocity of Stream be "s"

Man's Upstream Velocity = 2 = v-s

Man's Downstream Velocity = 3 = v+s

⇒2v = 5

v = 2.5

For 7 km, time taken = 7/2.5 = 2.8 = 2 hours and 48 minutes

The correct answer is Option (2) → 2 h 48 m