Multiple choice

The ratio of the speed of a boat in still water and the speed of stream is 4 : 1. If the difference between the distance covered by boat in downstream in 2 hours and upstream in 2 hours in 5 km. What is the speed of the boat in still water ?

  1. 8 kmph

  2. 7.5 kmph

  3. 12 kmph

  4. 5 kmph

  5. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let boat speed = 4x, stream speed = x. Downstream speed = 5x, upstream speed = 3x. In 2 hours downstream: 10x km. In 2 hours upstream: 6x km. Difference = 4x = 5 km, so x = 1.25. Boat speed in still water = 4x = 5 kmph. The question asks for boat speed, not the difference itself.

Keep practicing — related questions