A utility company has the following rate schedule for natural gas usage in a city's district: Monthly service charge of $8.80; Per therm service charge: 1st 25 therms: $0.6686/therm; Over 25 therms: $0.85870

(a) What is the charge for usaging 25 therms in one month?
(b) What is the charge for using 45 therms in one month?
(c) Construct a fraction that gives the monthly charge c for x therms of gas.

1 answer

well, for x <= 25,

f(x) = 8.80 + 0.6686x

Now what about for x > 25?