A man rows 12 km downstream in 3 hours and 6 km upstream in 2 hours. What is the speed of the stream?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 0.5 km/h.
Given: Downstream: 12 km in 3 hours → speed = 12 ÷ 3 = 4 km/h
Upstream: 6 km in 2 hours → speed = 6 ÷ 2 = 3 km/h
Let boat speed = b and stream speed = s
Downstream: b + s = 4
Upstream: b − s = 3
Add both equations = 2b = 7 → b = 3.5
Now s = 4 − 3.5 = 0.5