Multiple choice

If the speed of the stream is 20% of the speed of the ship in still water and it covers 240 km upstream in 150 minutes, then what is the downstream speed of the ship?

  1. 150 km/hr

  2. 144 km/hr

  3. 180 km/hr

  4. 160 km/hr

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

Let ship speed = x. Upstream speed = x - 0.2x = 0.8x = 240/2.5 = 96 km/hr. So x = 120 km/hr. Downstream speed = x + 0.2x = 1.2x = 144 km/hr.