We need to know the amount of food and spoiled food and each customer
First you subtract 25 from 5 which equals 20 then you multipliy 4 to 20 and you get 80...so 80 is your solution.
Given parameters:
Percentage gain = 300%
Selling cost last year = $2420
Unknown:
Selling cost this year = ?
Solution:
To solve this problem;
Profit percent = 
300 = 
3 = 
S- 2420 = 7260
S = $9680
To make a 300% gain, Jefferson Middle school needs a $9680 from fundraiser sales this year.