Math stuff I need help on

Question

You can send and receive text messages on your cell phone for $0.12 a message your cell phone provider also offers a plan for an unlimited number of messages for $4 per month. How many text messages must you send and receive a month to make the unlimited plan a better buy?

Answer 1

4/.12 = 400/12 = 100/3 = 33 1/3 messages

for 33 messages you're better off paying per message

for 34 or more messages it's cheaper with the unlimited plan

34 x .12 = $4.08 You save 8 cents if you do 34 messages per month on the unlimited plan

33 x 12 = $3.96 You lose 4 cents if you do 33 messages per month on unlimited plan