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A man swims for 3 hours downstream and then 3 hours upstream. In his whole process, he covers a total distance of 18 km. If the speed of the stream is 2 km/hr. Find the difference in the distance covered by him in downstream and upstream journey.

A man swims for 3 hours downstream and then 3 hours upstream. In his whole process, he covers a total distance of 18 km. If the speed of the stream is 2 km/hr. Find the difference in the distance covered by him in downstream and upstream journey. Correct Answer 12 km

Given:

A man swims for 3 hours downstream and then 3 hours upstream.

Total Distance covered = 18 km

If the speed of the stream is 2 km/hr.

Assumption:

Suppose the speed of the man in still water = a km/hr

Formula used:

Upstream speed = Speed of the man in still water - Speed of current

Downstream speed = Speed of the man in still water + Speed of current

Calculation:

⇒ 3 × (a + 2) + 3 × (a - 2) = 18

⇒ 3a + 6 + 3a - 6 = 18

⇒ 6a = 18

⇒ a = 3 km/hr

∴ Required difference = (3 + 2) × 3 - (3 - 2) × 3 = 12 km

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