Discussion Forum



Each of the questions given below consists of two statements numbered I and II given below it. Please read the questions carefully and decide whether the data provided in the statement(s) is / are sufficient to answer the given question.

1)

A man takes a total time of $3$ hours to swim down stream from $A$ to $B$ and back from $B$ to $A$. Find the speed of the man in still water ?

I. The river current speed is $1$ km/hr.

II. The distance between $A$ and $B$ is $4$ km.


A) I alone sufficient while II alone not sufficient to answer

B) II alone sufficient while I alone not sufficient to answer

C) Either I or II alone sufficient to answer

D) Both I and II are not sufficient to answer

E) Both I and II are necessary to answer

Answer:

Option E

Explanation:

I. Speed of the current $=1$ km/hr.

II. $AB$ $=4$ km.

Let the speed of the man in still water be $x$ km/hr. Then,

$\frac{4}{(x+1)}+\frac{4}{(x-1)}$ $=3$.

This gives $x$.

$\therefore$ Correct answer is (E).