The phone company Ringular has a monthly cellular plan where a customer pays a flat monthly fee and then a certain

Question

The phone company Ringular 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 480 minutes, the monthly cost will be $117. If the customer uses 700 minutes, the monthly cost will be $161.

A) Find an equation in the form y=mx+b,y=mx+b, where xx is the number of monthly minutes used and yy is the total monthly cost of the Ringular plan.

Answer: y=y= 

 

B) Use your equation to find the total monthly cost if 615 minutes are used.

Answer: If 615 minutes are used, the total cost will be  dollars.

Answer 1

y= 117 = 480x + Fixed monthly Fee

y= 161 = 700x + Fixed monthly Fee

subtract 1st from 2nd to eliminate all but one variable

44 = 220x

x =44/220 = $0.20 = 20 cents per minute

F = 117 -480(.2) = 117-96 = $21 per month Fee

y= 0.2x +21

y= .2(615) +21 = 123+21 = $144 for 615 minutes