Q. A boatman rows 1 km in 5 minutes, along the stream and 6 km in 1 hour against the stream. The speed of the strean is :
Answer: 3 km/hr
Notes: Speed of current = $latex \frac{Rate Downstream - Rate Upstream }{2}&s=1$ $latex =>\frac{1}{2}\left ( 12-6 \right )&s=1$ $latex =>\frac{1}{2}\times 6=3 km/hr&s=1$ Hence option [D] is the right answer.

3