Multiple choice

A man rows downstream to some destination and returns in 3 hours. If the speed of the boat in still water and the speed of stream are 6 km/h and 3 km/h, respectively , then the distance of the destination from the starting place is:

  1. 6.75 km

  2. 5.55 km

  3. 3.25 km

  4. 4.20 km

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

Speed of boat in still water = 6 km/h, speed of stream = 3 km/h. Downstream speed = 6 + 3 = 9 km/h. Upstream speed = 6 - 3 = 3 km/h. Total time = 3 hours. Let distance = d km. Time downstream + Time upstream = d/9 + d/3 = d/9 + 3d/9 = 4d/9 = 3. Solving: 4d = 27, d = 6.75 km.