Question

Bob swam 4 kilometers against the current in the same amount of time it took him to swim 12 kilometers with the current. The rate of the current was 2 kilometers per hour. How fast would Bob swim if there were no current?

Answer 1

Speed of the bob when there is no current is 4 km/hr

Step-by-step explanation:

Let the Bob swam v km/hr without the current '

Speed of current is 2 km/hr

So speed in the direct of current = v+2 km/hr

And speed against the direction of current = v-2 km/hr

It is given that Bob swam 4 km against the current in the same time as swam 12 km in direct of current , means time is same

We know that time
`=(distance)/(speed)`

So
`(4)/(v-2)=(12)/(v+2)`

`4v+8=12v-24`

8 v = 32

v = 4 km/hr

So speed of the bob when there is no current is 4 km/hr