Question

A candy factory wants to compare a new machine to their current machine. Both machines produce y boxes of candy for every hour x. The current machine is represented by the equation f(x). The new machine is represented by the equation g(x).
f(x) = 15x + 90
g(x) = 30x + 30


After what number of hours will the amount of candy produced be the same for both machines?

Answer 1

Set f(x) = g(x):

15x + 90 = 30x + 30
90 − 30 = 30x − 15x
60 = 15x
x = 4

After 4 hours both machines have produced the same amount (150 boxes).