An automobile cooling system has a capacity of 17qt. Initially, the system contains a mixture of 2 gal of antifreeze and 9 qt of water. Water runs into the system at the rate of 1 gal/min and the homogeneous mixture runs out a petcock at the same rate. How much anti freeze remains in the system after 5 min?

First I converted the units but after that, I don't know how to solve it.