Jane has a pre-paid cell phone with Splint. She can't remember the exact costs, but her plan has a monthly fee and a charge for each minute of calling time. In June she used 100 minutes and the cost was $54.00. In July she used 660 minutes and the cost was $138.00.

The costs of the plan are $0.15 per minute and a monthly fee of $39

Step-by-step explanation:

Let

x ----> the number of minutes used

y ----> is the total cost

step 1

Find the slope of the linear equation

The formula to calculate the slope between two points is equal to

we have the ordered pairs

(100,54) and (660, 138)

substitute

step 2

Find the equation of the line in point slope form

we have

substitute

step 3

Convert to slope intercept form

Isolate the variable y

therefore

The costs of the plan are $0.15 per minute and a monthly fee of $39

3

step-by-step explanation: