Question 260813
Plan A charges $25 per month for unlimited calls.
Plan B charges $13 per month plus $.06 per call.


You want to know when plan A costs less than plan B.


set up an equation as follows:


Cost for Plan A = $25.00


Cost for Plan B = $13.00 + .06 * x


x = number of calls per month.


you want to know when plan A Costs are smaller than plan B costs.


your equation is:


Plan A Costs < Plan B costs.


this becomes:


25 < 13 + .06 * x


subtract 13 from both sides of this equation to get:


25 - 13 < .06 * x


simplify to get:


12 < .06 * x


divide both sides of this equation by .06 to get:


12/.06 < x


simplify to get:


200 < x


this is the same as:


x > 200


Plan A at $25.00 per month will be cheaper when the number of minutes used per month is > 200.


200 should be the break even point.


200 * .06 + 13 = 12 + 13 = 25.


when the minutes go above 200, plan A at $25 per month will be cheaper.


at 201 minutes, plan B costs .06 * 201 = $12.06 + $13.00 = $25.06 which is more expensive than plan A.