An Internet bookstore charges $20 shipping for orders under $100 but provides free shipping for orders of $100 or more. The cost C of an order is a function of the total price x of the books purchased, given by
C(x) = {x + 20 if x < 100
{x if x > 100
Find C(55), C(90), C(100), and C(110).
C(55) = $
C(90) = $
C(100) = $
C(110) = $