A certain cellular phone plan charges $29.00 per month plus $0.15 for each minute of usage. The monthly charge is given by the formula monthly charge = 0.15x+29, where x represents the number of minutes of usage per month. What is the charge for a month with 330 minutes of usage? Write your answer to two decimal places as money is traditionally written.
Let
y -----> the monthly charge
x ----> number of minutes
we have
y=0.15x+29
For x=330 min
substitute
y=0.15(330)+29
y=$78.50
answer is $78.50