Question

The ratio of the speed of a boat downstream and speed of the stream is 9:1. If the speed of the current is 3 km per hr, find the distance travelled by the boat upstream in 5 hours.
A. 100 km
B. 98 km
C. 109 km
D. 105 km
E. 112 km

Answer 1

Man's speed with the current = 15 km/hr
=> speed of the man + speed of the current = 15 km/hr

speed of the current is 2.5 km/hr
Hence, speed of the man = 15 - 2.5 = 12.5 km/hr

man's speed against the current = speed of the man - speed of the current
= 12.5 - 2.5 = 10 km/hr

Answer 2

the answer is 10 km/hr