<PRE><B>Question 1172492</B>
let f = what she spent on food
let s = her salary
first equation is f = .2 * s
when her salary increased by 10%, her food expenditure increased by 50 dollars.
second equation is:
f + 50 = .2 * 1.10 * s
in the second equation, replace f with 2 * s from the first equation to get:
.2 * s + 50 = .2 * 1.10 * s
simplify to get:
.2 * s + 50 = .22 * s
subtract .2 * s from both sides of the equation to get:
50 = .02 * s
solve for s to get:
s = 50 / .02 = 2500
her salary was 2500
her food expenditure was .2 * 2500 = 500
when her salary went up 10%, her salary was 2500 * 1.10 = 2750.
her food expenditure went up 50 dollars to be 550.
550 / 2750 = .2
the proportion remained the same, confirming the solution is correct.
the solution is her original salary was 2500 dollars.


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