Question

Gloria has a gallon of paint to cover 500 square feet of drywall. She pointed out that for 10,000 square feet she needs 20 gallons of paint. Let's say the output (the range) is going to tell us how many gallons of paint to buy at the hardware store. The input will be the square footage required to be covered in the paint. Can someone write a function that describes this relationship?

Answer 1

let x = area to be painted (in sq ft)
let y = gallons of paint needed
therefore, using the second statement of the problem, we can find the ration of sq ft area painted per gallon:
10000 sq ft / 20 gallon = 500 sq ft / gallon
thus, to get the number of gallons needed, we divide the area surface to be painted by this ratio, so the function becomes:

y = x / 500

for instance we want to paint 1500 sq ft of drywall,, thus the number of gallons needed is:
y = 1500 / 500 = 3 gallons

hope this helps~ :)