Hard question I don’t know

Question

The siding of a house is 2250 square feet. The siding needs two coats of paint. The table shows information about the paint. 1 gallon is $29 and 1 quart is $18. 1 gallon can cover 320 square feet and 1 quart can cover 80 square feet. 1. What’s the minimum cost of the paint to complete the job? 2.how much paint is left over?

Answer 1

x = number of 1 gallon paints

y = number of 1 quart paints

x = 2250/320 = 7.0312 = 7 gallons (must round down to nearest whole number)

7*320 = 2240 sq ft (the amount of square feet that 7 gallons of paint cover)

2250-2240 = 10 sq ft (how much square feet is left to cover)

y = 1 quart (to cover the 10 sq ft left)

29x + 18y = total cost

29(7) + 18(1) = $221

10/80 = 1/8 quart paint used

1 - 1/8 = 7/8 quart paint left

answers: $221 and 7/8 quart paint left