Question

A boat covers 12 km downstream in 2 hours and returns the same distance upstream in 3 hours. The speed of the stream is

• A. 2 km/h
• B. 1 km/h
• C. 1.5 km/h
• D. 0.5 km/h

Hint:

Stream speed is half the difference between downstream and upstream speeds.

Answer 1

The Correct Option is B

Step 1: Let boat be $b$ and stream $s$.
Then $b+s=6$ and $b-s=4$.
Step 2: Subtract the equations.
$2s=2$, so $s=1$ km/h.
\[\boxed{1\ \textrm{km/h}}\]