The phone company NextFell has a monthly cellular plan whera customer pays a flat monthly fee and then a certain amount of money per minute used on the phone.

Question

The phone company NextFell has a monthly cellular plan where a customer pays a flat monthly fee and then a certain amount of money per minute used on the phone. If a customer uses 500 minutes, the monthly cost will be $83. If the customer uses 530 minutes, the monthly cost will be $86.

a.) Find an equation in the form y=mx+b where x is the number of monthly minutes used and yy is the total monthly of the NextFell plan.

answer y=

Do not use any commas in your answer.

B) Use your equation to find the total monthly cost if 631 minutes are used.

Answer: If 631 minutes are used, the total cost will be ______  dollars.

Answer 1

C= mt + b

83 = m(500) + b

86 = m(530 + b

subtract 1st equation from 2nd

3 = 30m

1 =10m

m= 1/10

83 = (1/10)500 + b

83= 50 + b

b =83-50 = 33

b = 33

C = (1/10)t + 33 = 10 cents per minute plus $33 monthly fee

C= (1/10)631 + 33 = 63.1 + 33 = 96.1 = $96.10 for 631 minutes