Wouldn't the answer be: 435.84m
She needs to score a 91 on her next test because 85+78+77+69+91=400 and 400 divided by 5 gives you a mean of 80.
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
0.43 =
3/100 = 0.03
+
4/10 = 0.4
0.03 + 0.4 = 0.43.
Hope this helped☺☺