A person can swim downstream at the speed of \(6 \mathrm{kmph}\) and upstream athe speed of \(2 \mathrm{kmph}\). What is the speed of swimming in still water?
A. 4 B. 2 C. 9 D. 16
Correct Answer: A
Explanation
let \(x\) be the speed of the person in still water and \(y\) the speed of the current Note: Swimming downstream is in the same direction as the current thus: \(x+y=6 \ldots . \ldots \ldots\) (1) and swimming upstream is in the opposite direction to the current thus: \(x-y=2 \ldots \ldots . \ldots \ldots\) (2) solving (1) and (2) simultaneously \(2 x=8\) \(x=4 \mathrm{kmph}\)