To answer the problem we let x and y be the number of fruit pies and fruit juice that Mr. Sanchez and Mr. Kelly's classes sold, respectively. The system of linear equation that would best represent the scenario above is,
x + y = 79
1.65x + 1.36y = 118.17
The values of x and y are 37 and 42, respectively.
(a) The items above answer the first question
(b) amount of money earned by both classes:
Mr. Sanchez's: (1.65)(37) = $61.05
Mr. Kelly's: (1.36)(42) = $57.12
Thus, Mr. Sanchez's class earned more money.
(c) $61.05 - $57.12 = $3.93.