Answer:
cheeseburger has 1050 calories, fries have 400 calories
Explanation:
set up a pair of simultaneous equations
let c be the number of calories in a cheeseburger and f the calories in fries
3c + 3f = 4350 → (1)
7c + 6f = 9750 → (2)
multiplying (1) by - 2 and adding the result to (2) will eliminate f
- 6c - 6f = - 8700 → (3)
add (2) and (3) term by term to eliminate f
(7c - 6c) + (6f - 6f) = 9750 - 8700
c + 0 = 1050
c = 1050
substitute c = 1050 into either of the 2 original equations and solve for f
substituting into (1)
3(1050) + 3f = 4350
3150 + 3f = 4350 ( subtract 3150 from both sides )
3f = 1200 ( divide both sides by 3 )
f = 400
A cheeseburger has 1050 calories, fries have 400 calories