Difficulty Level: Hard
Stats: 1,379 / 4,202 ( 32.82% ) got this right

A motorboat, whose speed in 15 km/hr in still water goes 30 km downstream and comes back in a total of 4 hours 30 minutes. The speed of the stream (in km/hr) is:

  • 2 km/hr
  • 3.25 km/hr
  • 4 km/hr
  • 4.5 km/hr
  • 5 km/hr