Question

Suppose a 15-minute call costs $5.26, and a 30-minute call costs $10.24. Find a formula relating time (in minutes) and cost (in dollars).
How do you do this???

Answer 1

You need to find the slope, and create a line (function) by getting it into the slope point formula.

your two points are

15,5.26
30,10.24

y2-y1/x2-x1

slope=0.332x

point slope formula is y-y1=m(x-x1)

y-10.24=0.332(x-30)

y=0.332x+0.28<<<<your function