A boat covers a distance of 30 km downstream in 2 hours while it takes 6 hours to cover the same distance upstream. What is the speed of the boat in km/hr ?
A. 5
B. 7.5
C. 10
D. 12
Answer : C. 10
Explanation :
- Speed of boat downstream
= Distance covered / Time taken
= 30/2
= 15 km/h - Now, speed of boat upstream
= Distance covered / Time taken
= 30/6
= 5 km/h - Now, speed of boat = (Speed downstream + Speed upstream)/2
= (15 + 5)/2
= 20/2
= 10 km/h.
