Question

One quart of water-resistant paint covers 75 square feet. A swimming pool is in the shape of a rectangular prism with a length of 20 feet, a width of 10 feet, and a height of 5 feet. How many quarts should you buy to paint the swimming pool with two coats of paint?

Answer 1

18.66 quarts of paint is needed to paint the swimming pool with two coats of paint

Solution:

Given that,

A swimming pool is in the shape of a rectangular prism

Length = 20 feet

Width = 10 feet

Height = 5 feet

Find the surface area of prism

$A=2(wl+hl+hw)$

Where, "l" is the length and "w" is the width and "h" is the height

$A = 2(10 \times 20 + 5 \times 20 + 5 \times 10)\\\\A = 2(200+100+50)\\\\A = 2 \times 350\\\\A = 700$

Thus surface area area of prism is 700 square feet

Given that,

One quart of water-resistant paint covers 75 square feet

Therefore,

1 quart paint = 75 square feet

x quart = 700 square feet

This forms a proportion

$1 \times 700 = 75 \times x\\\\x = \frac{700}{75}\\\\x = 9.33$

Thus 9.33 quarts of paint is needed to cover 700 square feet

How many quarts should you buy to paint the swimming pool with two coats of paint

For two coats of paint we need = 9.33 + 9.33 = 18.66 quarts of paint