Janet is painting her shed. She buys some gallon-sized paint cans that cost $15 each and 2 quart-sized paint cans that cost $4 each. The cost of Janet's total purchase is $53. Write and solve an equation to determine the number of gallons of paint that Janet purchased.

1 gallon cost $15

1 quarts cost $4

1 quarts = 1/4 gallon

15x for number of gallon cans

2 cans at $4 each = $8

15x + 8 = 53

Subtract 8 from both sides:

15x = 53-8

15x = 45

Divide both sides by 15:

x = 45/15

x = 3

She bought 3 gallon cans of paint

Plus she bought 2 quart cans, which is equal to a half gallon.

She bought a total of 3.5 gallons of paint.