Answer
Find out the how much did each student recieve .
To prove
Let us assume that each student earned in the bake sell be x .
As given
Three students earned $48.76 at the bake sell.
The students split the earnings evenly i.e earning is divided into three equal parts .
Than the equation becomes

Solving the above
x = $16.25(approx)
Therefore the each student recieve $16.25(approx) .
Hence proved
He earned $325 because 900 divided by 4% = $225! :)
Answer:
Plug x-7 in for y, in the bottom equation.
x - 7 = 2 + 2x - 4
x - 7 = 2x - 2
x = 2x + 5
-x = 5
x = -5