Answer:$378.95
Explanation:
Change it all to fractions.
3/10 of her salary on rent
2/5 of her salary on entertainment
1/4 of her salary on living expenses.
Add them
3/10 + 2/5 + 1/4 = 6/20 + 8/20 + 5/20 = 19/20*S
(19/20)*S = 7200
S = 7200*20/19
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She saved the remaining 1/20 of S = 7200/19
saved =~ $378.95