Kareem swam 4 kilometers against the current in the same amount of time it took him to swim 16 km with the current. the rate of the current was 3 km/h how fast word kareem swim if there is no current?

Let the speed of Kareem be x km/h
since time=distance/speed
then:
Time taken to swim 16km will be:
16/(x+3)

Time taken to swim 4km will be:
4/(x-3)
thus
16/(x+3)=4/(x-3)
16(x-3)=4(x+3)
16x-48=4x+12
16x-4x=12+48
20x=60
x=60/20
x=3 km/h

A< 2 = z