Question

A telephone company offers two billing plans for local calls. Plan A charges $37 per month for unlimited calls and Plan B charges $18 per month plus $0.05 per call. Write and solve an inequality to find the number of monthly calls for which Plan A is more economical than Plan B.

Answer 1

0.05m + 18 < 37

Explanation:

Inequalities always hurt my head, so let me offer this: at how many calls will you pay the same for each plan? From there you can figure out the inequality piece.

Plan A: $37 Constant, doesn't change.

Plan B: $18 + 0.05m Where m = number of calls made.

So, when 18 + 0.05m evaluates to 37, that's the number of calls that makes the two plans equal. So set the two plans equal to each other:

18 + 0.05m = 37 Then simplify:

0.05m = 19 Subtracted 18 from each side.

m = 19/0.05 Divided both sides by 0.05.

m = 380 calls

That's the point at which you pay the same amount for each bill. If you make more than 380 calls per month, then Plan A is cheaper. If you make less than 380 calls, then Plan B is cheaper.

So I suppose the inequality would just be:

0.05m + 18 < 37

I hope the discussion helped, rather than just tell you the answer.

Take care.