Steven switched phone carriers to one that charges $40 a month for unlimited calls. Assuming he has been spending $75 a month on phone service, how much will he save in 18 months?
On his old contract, Steven was spending $75 per month.
On his new contract, Steven is spending $40 per month.
That means Steven is saving $75 - $40 = $35 per month
Therefore, over 18 months Steven will save 18*35 = $630
Answer: $630