Solve this multiple-choice question and choose the correct option.

A sailor sails a distance of 48 km along the flow of a river in 8 h. If it takes 12 h to return the same distance, then the speed of the flow of the river is?

0.5 km/h
1 km/h
1.5 km/h
2 km/h

Correct Answer: 1 km/h

Explanation:

Let speed of the flow of water be x km/h and rate of sailing of sailor be y km/h. Downstream speed (x + y) = 48/8 ⇒ x + y = 6 ....(i) and upstream speed x - y = 4 ...(ii) On solving Eqs. (i) and (ii), we get y = 1 km/h

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