An athlete plans to row upstream a distance of 6 kilometers and then return to his starting point in a total time of 4 hours. If the rate of the current is 2 km/hr, how fast should he row.

He should row at the speed of 12 kilometers per hour.

Step-by-step explanation:

Given:

An athlete plans to row upstream a distance of 6 kilometers and then return to his starting point in a total time of 4 hours.

The rate of current is 2 km/hr.

Now, to find how fast should he row.

Let speed of the athlete row be .

Distance = 6 kilometres.

So, to get the time of upstream:

Rate of upstream = .

Time of upstream =

Now, to get the time of downstream:

Rate of upstream=

Time of downstream = .

Now, as given total time 4 hours.

Thus, we set an equation:

Time of upstream + time of downstream = total time.

Multiplying both sides by 6 we get:

Dividing both sides by 2 we get:

Therefore, he should row at the speed of 12 kilometers per hour.