Discuss Forum

1. A certain river has a current of 3 miles per hour. A boat takes twice as long to travel upstream between two points as it does to travel downstream between the same two points. What is the speed of the boat in still water?

  • A. 3 miles per hour
  • B. 3 miles per hour
  • C. 3 miles per hour
  • D. 3 miles per hour

Answer: Option C

Explanation:

Let the boat speed and current flow be U and V respectively. According to the question, the relative speed of boat downstream (U + V) is twice as that of upstream (U - V).

So,  U + V = 2(U - V)

or, U + V = 2U - 2V

or, 2U - U = V + 2V

or, U = 3V = 3 x 3 =  9 km per hour

Post your comments here:

Name:
Mobile:
Email:(Optional)

» Your comments will be displayed only after manual approval.