You know that the height of the smaller cylinder is 6 cm and the height of the larger cylinder is 18 cm, then you can find the volume ratio. This is:
Knowing that the volume of the larger cylinder is 40,635 cubic centimeters, you need to multiply it by the volume ratio to find the volume of the smaller cylinder.
It would take her 12 minutes because if you mutipy 2/3 by 3/2 then you get 1 (as in one mile) and then you have to do that to the other side too so then you multiply 8 by 2/3 and get 12