Carl and Lisa are renting moving trucks from same company. They pay a fee of x dollars just to rent the truck, and y dollars per mile they drive, Carl drives 150 miles and pays $215 Lisa drives 120 miles and pays $176 dollars. Find the amount of the original fee and cost per miles.

First you have to make equations for Carl and Lisa

x + 150y = 215

x + 120y = 176

Now you can solve by substitution or elimination, I'm going to use elimination, so I'm going to multiply the bottom equation by negative one and solve

x + 150y = 215

-x - 120y = - 176

30y = 39

y = 1.3

So it cost $1.30 per mile

Now plug the number into one of the original equations to get x

x + 150 (1.3) = 215

x + 195 = 215

x = 20

So the fee for renting the truck is $20