Question

A painter made the table below to show the amount of paint it takes to cover a certain amount of square feet. The amount of paint varies directly with the area of each wall.

Amount of Paint and Size of Wall
Area of wall feet squared, x
64
144
400
Amount of paint (pints), y
4
9
25

How much paint should the painter expect to use to paint a wall with an area of 256 square feet?
16 pints
32 pints
128 pints
225 pints

Answer 1

Since y varies directly with x, y = kx. From 4 = k(64) so k = 4/64 = 1/16. Thus y = x/16. For x = 256, y = 256/16 = 16 pints.

Answer: 16 pints.