person A swims in (2*r/3)hrs.
so,speed of person B=(2*pi*r*3/2*r)km/h.
=3*pi km/h.
Okey, person A swims across a lake at 3km/h, where person B jogs around. Person A use the same time as Person B to swim across of the lake as Person B runs around it one time.
What's the speed of Person B?
To long since I've done this stuff so stuck atm... Any help would be greatly appriciated!
Could it be