Answer:
A -- She saves 200₤.
B -- She will have 28₤ after buying presents.
Explanation:
If two boxes = 20 then one box will be 10. Now we count all boxes. There are 20 boxes... 20 x 10 = 200, so she saves 200₤. If she spends 172₤ on Christmas presents she will have 28₤. (200 - 172 = 28).