Question

A cell phone company charges a monthly rate of $12.95 and $0.25 a minute per call. The bill for m minutes is $21.20

a) Write an equation that models this situation.

b) How many minutes were charged on the bill?​

Answer 1

• Fixed amount=12.95$=b
• Rate of change=0.25$ =m

Let minutes be x

Equation in slope intercept form

`\\ \tt\longmapsto y=mx+b=0.25x+12.95`

Now for second part

`\\ \tt\longmapsto 0.25x+12.95=21.2`

`\\ \tt\longmapsto 0.25x=8.25`

`\\ \tt\longmapsto x=33min`