You have a limit of $300 that you can spend for a rental car on your vacation this summer. you have found a deal where you can rent a car for a daily rate of $30 plus a fee of $0.20 per mile driven. if you want to be able to keep the car for four days, how many miles can you drive?

From the problem
you can get the equation
4(30+0.20x) < 300

the 4 represents that it is within 4 days, the 30 is the daily fee, the 0.20 is the rate of per mile driven per day, and the 300 is how much money you have left to spend.

now we solve for x, first distribute the 4 into the parenthesis
120 + 0.80x < 300     then subtract 120 from both sides
-120              -120
and get   0.80x < 180   then divide both sides by 0.80
             /0.80       /0.80
therefore x = 225
so you can drive  225 miles.