Multiple choice

If the speed of a boat in still water is 25 km/hr and the speed of the current is 5 km/hr, then find the time taken by the boat to cover 135 km downstream.

  1. 5 hour and 30 minutes

  2. 4 hours

  3. 5 hours

  4. 4 hours and 30 minutes

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Downstream speed = boat speed + current speed = 25 + 5 = 30 km/hr. Time = distance/speed = 135/30 = 4.5 hours = 4 hours 30 minutes. Option A incorrectly adds time, B and C are calculation errors.