The phone company Splint 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 310 minutes, the monthly cost will be $145.5. If the customer uses 570 minutes, the monthly cost will be $236.5.

A) Find an equation in the form where is the number of monthly minutes used and is the total monthly of the Splint plan. ?

Do no use any commas in your answer.

B) Use your equation to find the total monthly cost if 698 minutes are used.

Answer: If 698 minutes are used, the total cost will be ?

Question

The phone company Splint 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 310 minutes, the monthly cost will be $145.5. If the customer uses 570 minutes, the monthly cost will be $236.5.

A) Find an equation in the form  where  is the number of monthly minutes used and  is the total monthly of the Splint plan. ?   
   
Do no use any commas in your answer.

B) Use your equation to find the total monthly cost if 698 minutes are used.

Answer: If 698 minutes are used, the total cost will be ?

gw2011 · Answer

Let x=Amount per minute
Let y=Flat fee

570x+y=236.50
310x+y=145.50  Subtract this equation from the above one to get:

260x=91
x=91/260
x=$0.35 per minute  Substitute this value into one of the equations to find y:

310x+y=145.50
310(0.35)+y=145.50
108.50+y=145.50
y=$37 Flat fee

TC=37+0.35x
TC=37+0.35(698)
TC=37+244.30
TC=$281.30  This is the total cost for 698 minutes