# Math Help - Cost of Natural Gas

1. ## Cost of Natural Gas

On December 13, 1996 the Peoples Gas Company had the following rate schedule for natural gas usage in single family residences:

Monthly service charge 9.00
Per therm service charge
1st 50 Therm $.36375/therm Over 50 Therms$.11445/therm
Gas charge \$.3256/therm

a) Wha is the charge for using 50 therms in a month?
b)What is the charge for using 500 therms in a month?
c) construct a function that relates the monthy charge C for x therms of gas
d) Graph this function

$C = 9 + (.3256)T + (.36375)T$ ... $T \leq 50$
$C = 9 + (.3256)T + (.11445)T$ ... $T > 50$