Question 36
A boat covers 72 km downstream in 6 hours and upstream in 9 hours. The speed of the boat is:
Solution
Let us assume the speed of boat = B km/hr and speed of stream = S km/hr.
Downstream: B+S = 72/6 = 12.
Upstream: B-S = 72/9 = 8.
Adding both equations: 2B = 20
==> B = 10 km/hr.
