Question

cell phone a cost $70 per month and comes with a free $500 phone cell phone plan B cost $50 per month but does not come with a phone if you buy the $500 phone and choose Plan B how many months is it until your cost is the same as plan A's​

Answer 1

Okay, not too bad, this one. Let's organize first by identifying each plan:

A = 70*M

B = 500 + 50*M

Costing the same means equal, so we have the equation:

70M = 500 + 50M

-50M -50M

20M = 500

20M / 20 = 500 / 20

M = 25 months

Explanation: