Multiple choice

Naimish swims (12) km in an hour in still water. What distance he will cover against the river in (3.5) hours in a river flowing at the rate (2.5) km/hr?

  1. $30 km$
  2. $33.25 km$
  3. $32.25 km$
  4. $37.75 km$
  5. $23.75 km$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When swimming against the current (upstream), effective speed = swimmer's speed in still water - river speed = 12 - 2.5 = 9.5 km/hr. Distance = Speed × Time = 9.5 × 3.5 = 33.25 km. Against the current means subtracting the river's speed from the swimmer's speed.