The speed of the boat in still water in 12 kmph. It can travel downstream through 45 kms in 3 hrs. In what time would it cover the same distance upstream?
8 hours
6 hours
4 hours
5 hours
Explanation:
Speed of the boat in still water = 12 km/hr
Speed downstream $=\dfrac{45}{3}$ = 15 km/hr
Speed of the stream = 15-12 = 3 km/hr
Speed upstream = 12-3 = 9 km/hr
Time taken to cover 45 km upstream $=\dfrac{45}{9}$ = 5 hours