Mary is decorating her bedroom and decides to paint three of the walls. Each of the walls measures 12 feet by 10 feet. If a quart of paint will cover 90 square feet, how many quarts does she need

Sagot :

First, we'll get the total area of the three walls to be painted.
12ft x 10ft x 3walls = 360 sq. ft.
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Since you are given that a quart of paint will cover 90 sq ft then,
360sq.ft. x (1qt/90sq.ft.) = 4 quarts or 1 gallon.
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Therefore 4 quarts of paint will be needed.
First, we need to know the area of the each of the walls and multiply it by 3.
[tex]A=lw\\A=(12ft.)(10ft.)\\A=120ft.^2[/tex]
120 ft.²  ×  3 = 360 ft.²

[tex] \frac{360ft.^2}{90ft.^2} =4[/tex]

Therefore, the answer to your question is 4 quarts of paint.