John and Priya went for a small picnic. After having their lunch Priya insisted to travel in a motor boat. The speed of the motor boat was 20 km/hr. Priya being a Mathematics student wanted to know the speed of the current. So she noted the time for upstream and downstream. She found that for covering the distance of 15 km the boat took 1 hour more for upstream than downstream.
Let speed of the stream be x km/hr. then speed of the motorboat in upstream will be

Options

A. `20 km//hr`
B. `(20+x) km//hr `
C. `(20-x) km//hr`
D. `2 km//hr`

Answer

C

Explanation

In this case speed of the motorboat in upstream will be (20 - x) km/hr.
Thus (c) is correct option.