Multiple choice

A boat can travel 28.8 km downstream in 64 minutes. If the speed of the current is 3 km/hr., how much time the boat will take to travel 168 km upstream?

  1. 24 hours

  2. 16 hours

  3. 8 hours

  4. 7 hours

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

Downstream speed = 28.8km / (64/60)hr = 27 km/hr. Boat speed in still water = Downstream speed - Current speed = 27 - 3 = 24 km/hr. Upstream speed = Boat speed - Current = 24 - 3 = 21 km/hr. Time for 168 km upstream = 168/21 = 8 hours. However, the marked answer assumes boat speed calculation from current speed differently.