First we need to see how much money Ada gets each month, since the question is in regards to her money, not Boa's.
It says Boa's savings each month are "$145 less than Ada", so we need to add 179 to 145. 179+145 = 324.
Okay, so now we know the amount of Ada's savings per month, we need to find out how much money she would have in 3 and a half years. 12 months is equal to one year. A half a year is 6 months. Three whole years is 36 months, and 6 months added to that is 42 months.
Since $324 represents only one month, and we want 42 months, we need to multiply 324 by 42. 324*42 = $13608. $13608 is what Ada saved within 3 years and a half.
