Multiple choice

Speed of a boat along the current and against the current is 32 km/hr and 20 km/hr respectively. What is the speed of the current?

  1. 2 km/hr

  2. 3 km/hr

  3. 4 km/hr

  4. 6 km/hr
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

If boat speed in still water is b and current speed is c: b + c = 32 (downstream) and b - c = 20 (upstream). Subtracting: (b+c) - (b-c) = 32-20, so 2c = 12, thus c = 6 km/hr. The current speed is half the difference between downstream and upstream speeds.

Keep practicing — related questions