Question 262697
If a boat is moving in upstream with velocity of 14 km/hr and goes downstream with a velocity of 40 km/hr, then what is the speed of the stream ? 
(a) 13 km/hr (b) 26 km/hr (c) 34 km/hr (d) none of these 


Let v be the velocity of the boat and c the current. Then we have:

Upstream:

1.) v - c = 14

Downstream:

2.) v + c = 40 

From 1.) we have v = 14 + c

Substitute 14 + c for v in equation 2.):

(14 + c) + c = 40
2c = 40 - 14 
2c = 26
c = 13