A man swimming downstream overcomes a float at a point M. After travelling distance D,he turned back and passed the float at a distance of `D//2` from the point M. Then the ratio of speed of swimmer with respect to still water to the speed of the river will be

Options

A. 2
B. 3
C. 4
D. 2.5

Answer

B

Explanation

Time taken by man to go from M to P and then P to N = time taken by float to go from M to N.
`(D)/(v + u) + (D)/(2(v - u)) = (D)/(2 u)`
Simplify to get `(v)/(u) = 3`.