A fisherman is rowing a boat. He takes 6 hours to row 48 km upstream whereas he takes 3 hours to go to the same distance downstream.

Based on the above information, which of the following are correct?

(A) His speed of rowing in still water is 10 km/hour.

(B) The speed of the stream is 3 km/hour.

(C) The average speed of the fisherman is 32/3 km/hour.

(D) The speed of the stream is 4 km/hour.

Choose the correct answer from the options given below:

The fisherman rows against the current when going upstream (slower) and with the current when going downstream (faster).

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Upstream Speed:

Distance = 48 km, Time = 6 hours

Upstream Speed $= \dfrac{48}{6}$

Upstream Speed $= 8$ km/h

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Downstream Speed:

Distance = 48 km, Time = 3 hours

Downstream Speed $= \dfrac{48}{3}$

Downstream Speed $= 16$ km/h

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When rowing upstream: Speed in still water - Stream speed = 8 km/h

When rowing downstream: Speed in still water + Stream speed = 16 km/h

Speed in still water $= \dfrac{\text{Upstream Speed + Downstream Speed}}{2}$

$= \dfrac{8 + 16}{2}$

$= \dfrac{24}{2}$

$= 12$ km/h

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Stream speed $= \dfrac{\text{Downstream Speed - Upstream Speed}}{2}$

$= \dfrac{16 - 8}{2}$

$= \dfrac{8}{2}$

$= 4$ km/h

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Total Distance = 48 + 48 = 96 km

Total Time = 6 + 3 = 9 hours

Average Speed $= \dfrac{\text{Total Distance}}{\text{Total Time}}$

$= \dfrac{96}{9}$

$= \dfrac{32}{3}$ km/h

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(A) Speed in still water is 10 km/h → Incorrect (It's 12 km/h)

(B) Stream speed is 3 km/h → Incorrect (It's 4 km/h)

(C) Average speed is 32/3 km/h → Correct

(D) Stream speed is 4 km/h → Correct

Therefore, statements (C) and (D) are correct.