Answer:
21 Months
Explanation:
If he already has $225, we can do 750 - 225 to get 525. $525 represents how much more money he needs to reach his goal of $750. So we can do 525 divided by 25, since that is how much he makes per month, giving us 21. 21 is how many months it will take until he gets to $750 without spending anything.