Answer:
Is Mary a guy? :|
Explanation:
I did this by just a good guess , not really the right way
2000*.45=900 ( 900 is the old savings)
2000*.2 =400 ( how much her salary went down by )
2000-400=1600 ( new salary )
1600*.45 = 720 ( 45% of new salary is new savings
900-720=180 ( change in savings is 180 , the amount the question asks for)
Mary's old salary was 2,000