8. The average weekly cost of childcare in the United States increased from $84/week to
$143/week from 1985 to 2011.

a) Write a linear function that approximates the average weekly cost (C) of child care
over time (t) starting in 1985.

b) Predict the weekly cost of childcare in 2019.

c) In about what year will the average cost have gone over $200/week?