What you do is 28,140 - 5% cause when you are doing a type of problem like this (trying to fins what was the last year) that means to subtract cause she now has 28,140 , and that was from a 5% raise but what she is trying to figure out is that how much did she have before the raise , so we are gong to grab the increased salary (28,140) with the raise percentage that made it increase (5%) , now you subtract , 28,140 - 5% = 26,733 .. I subtracted and found my answer :)
your answer is 26,733 hope this helps :)