A rental company charges a flat fee of x dollars for a floor sander rental plus y dollars per hour of rental. One customer rents a floor sander for 4 hours and pays $63. Another rents a floor sander for 6 hours and pays $87. Find the flat fee and the cost per hour for the rental.

Take 87-63 = 24, which is the difference of the 2 hours. Divide this by two to get the hourly rate, which is $12.

We can now set up the equation as follows:

4 (12) + x = 63

6 (12) + x = 87

Now solve for each:

4 (12) + x = 63

48 + x = 63

x = $15

6 (12) + x = $87

72 + x = 87

x = $15

Therefore, the Flat Fee = $15 and the Hourly rate = $12