May I have some help please?

Alexis needs to paint the four exterior walls of a large rectangular barn. The paint costs $28 per gallon, and each gallon covers 420 square feet. How much will it cost Alexis to buy enough paint to paint the barn?

Step-by-step explanation:

Assume the barn is 80 ft long, 50 ft wide, and 30 ft high

1. Area to paint

They will be painting two sides and two ends.

The sides are 80 ft × 30 ft.

The ends are 50 ft × 30 ft,

Area of sides = 2 × 80 ft × 30 ft =  4800 ft²

Area of ends = 2 × 50 ft × 30 ft =  3000 ft²

                                   Total area = 7800 ft²

2. Amount of paint needed

One gallon covers 420 ft².

They usually sell barn paint in whole gallons. Alexis will have to buy 19 gal of paint to cover the whole barn.

3. Total Cost

It costs $28 for one gallon of paint,

= 5

step-by-step explanation:

to find the 15th term substitute n = 15 into the nth term formula

= (- 3 × 15 ) + 50 = - 45 + 50 = 5

b, i believe, but not sure.