Saim can row 9 km/hr in still water. It takes him twice the time to row up as to row down. Find the rate of flow of the stream.

by

A) 1 km/h
B) 2 km/h
C) 3 km/h
D) 6 km/h

🧠 Explanation (Math):

Given: Still-water speed = 9 km/h; upstream time is twice downstream time; find stream speed
Step 1: Let stream speed = v; for same distance: t_up = d/(9 − v), t_down = d/(9 + v)
Step 2: Given t_up = 2 t_down ⇒ d/(9 − v) = 2d/(9 + v)
Step 3: Cross-multiply: 9 + v = 2(9 − v) ⇒ 9 + v = 18 − 2v ⇒ 3v = 9 ⇒ v = 3
Final Answer: 3 km/h