Synopsis IAS

Answer

Solution

UPSC Prelims

Mathematics

Theme:

Speed, Time and Distance / गति, समय और दूरी

Q74 2020, Speed, Time and Distance

A man takes half time in rowing a certain distance downstream than upstream. What is the ratio of the speed in still water to the speed of current?

• Let the speed of man in still water be x and the speed of current be y. Let the total distance be D.

So, Downstream speed = x + y

And Upstream speed = x – y

According to the question,

Time taken in rowing upstream = 2 × Time taken in rowing downstream

Or, D/(x – y) = 2 × [D/(x + y)]

Or, x + y = 2x – 2y

Or, x = 3y

∴ x : y = 3 : 1

Q 74. 2020, Speed, Time and Distance