Question

A phone company offers two monthly plans. Plan A costs $11 plus an additional $0.17

for each minute of calls. Plan B costs $16 plus an additional $0.13 for each minute of calls.

For what amount of calling in minutes do the two cost the same?
What is the cost when the two plans cost the same?

Answer 1

125 minutes of calling

It will cost $32.25 when the plans cost the same.

Explanation:

The first plan's expression would be:

11+.17x x being the number of minutes

The second plan's expression would be:

16+.13x

You must set the expressions equal to one another. So:

11+.17x=16+.13x

Then solve for x:

.17x=5+.13x

.04x=5

x=125

So the plans will cost the same after 125 minutes. To find the cost of the plans at that time, substitute 125 in for the x in one of the equations.

11+.17(125)=y y being the overall cost of the plan

11+21.25=y

32.25=y

To check your answer, you can substitute again in the other equation:

16+.13(125)=y

16+16.25=7

32.25=7