A car and a van are driving on a highway. The table shows the amount y (in gallons) of gas in the car's gas tank after driving x miles. The amount of gas in the van's gas tank after driving x miles is represented by the equation y=−1/12x+40. Which vehicle uses less gasoline per mile? How many miles must the vehicles travel for the amount of gas in each gas tank to be the same?
Miles traveled,x,Gallons of gas in tank,y, 60 15
120 13
180 11
240 9
The amount of gas in each tank is the same after _ miles.​