Question

A contractor finds that 7 gallons of paint will cover 1575 sq ft of wall area. How much wall area could be covered with 21 gallons of​ paint?

Answer 1

4725 square feet of wall area could be covered with 21 gallons of​ paint.

Explanation:

Given: 7 gallons of paint will cover 1575 sq ft of wall area.

We have to fine the wall area that could be covered with 21 gallons of​ paint.

Unitary method is a method in which we first find the value of a unit quantity and then multiply it with the desired quantity.

7 gallon of paint need to cover area = 1575 ft²

1 gallon of paint cover area =
`(1575)/(7)` ft²

Thus, 21 gallon of paint cover area =
`(1575)/(7)* 21=225 * 21` ft²

21 gallon of paint cover area =
`225 * 21=4725` ft²

Thus, 4725 square feet of wall area could be covered with 21 gallons of​ paint.

Answer 2

4725 ft²

Explanation:

21 gallons is 3 times 7 gallons, so we expect it to cover 3 times 1575 square feet.

3 × 1575 ft² = 4725 ft²

21 gallons will cover 4725 square feet of wall area.