Difference of speed of boat in downstream and upstream is 7km/hr and the time taken by the boat to travel 45 km in downstream is 80 minutes more than the
time taken to travel 13 km in upstream. Due to cyclone, speed of current becomes twice and thus it can cover D km in upstream in time which is equal to new speed of current. Find D? (Note: speed of boat in
still water is multiple of 5)

Options

A. 30
B. 24
C. 18
D. 21

Answer

To solve the problem step by step, let's break it down:

### Step 1: Define Variables
Let:
- \( x \) = speed of the boat in still water (in km/hr)
- \( y \) = speed of the current (in km/hr)