the cost of cell phone bill includes the monthly fee plus the charge per minute for every minute per month.The charge for 500 minutes is 80$.

Question

the charge for 1350 minutes is 131$.How much is the monthly fee and how much is the monthly fee and how much is the charge per minute ¿

Answer 1

The charge for 500 minutes is 80$

80 = 500x + b

 

the charge for 1350 minutes is 131$

131 = 1350x + b

-(80 = 500x + b)

51 = 850x

x = .06  This is the charge per minute

80 = 500x + b

80 = 500(.06) + b

80 = 30 + b

b = 50, the flat rate charge per month