Jill Tolbert, Teacher at Caroline County Schools, Numerade Educator

05:22

Prealgebra

Cost of Natural Gas In March 2014 , Laclede Gas had the rate schedule (on, right) for natural gas usage in single-family residences.
(a) What is the charge for using 20 therms in a month?
(b) What is the charge for using 150 therms in a month?
(c) Develop a function that models the monthly charge $C$ for $x$ therms of gas.
(d) Graph the function found in part $(\mathrm{c})$.
$$
\begin{array}{cl}{\text { Monthly service charge }} & {\$ 19.50} \\ {\text { Delivery charge }} \\ {\text { First } 30 \text { therms }} & {\$ 0.91686 / \text { therm }} \\ {\text { Over } 30 \text { therms }} & {\$ 0} \\ {\text { Natural gas cost }} \\ {\text { First } 30 \text { therms }} & {\$ 0.3313 / \text { therm }}\\ {\text { Over } 30 \text { therms }} & {\$ 0.5757 / \text { therm }}\end{array}
$$