Question

The function for the cost of materials to make a muffin is f(x) = Three fourths x + 3, where x is the number of muffins. The function for the selling price of those muffins is g(f(x)), where g(x) = 3x + 4. Find the selling price of 20 muffins.

Answer 1

So first let’s put g(f(x)) together by putting f(x) for every x in g(x)

We get g(f(x))=3(3/4x+3)+4 which is the selling price equation

Then you plug in 20 to find the selling price for 20 muffins.

g(f(x))=3(3/4(20)+3)+4

g(f(x))=3(60/4+3)+4

g(f(x))=3(18)+4

g(f(x))=54+4

g(f(x))=58

So the selling price will be $58 for 20 muffins.