what is the the caloric content of each item?

Question

Two cheeseburgers and one small order of fries contain a total of 1310 calories. Three cheeseburgers and two small orders of fries contain a total of 2080 calories. Find the caloric content of each item.

Answer 1

2c + f = 1310

3+ 2f = 2080

multiply 1st equation by 2, then subtract 2nd equation to get

4c +2f = 2620

4c-3c = 2620-2080

c = 540 calories per 1 cheeseburger

f = 1310=1080 = 230 calories per 1 small fries