SOLUTION: This is the question I need help on: At McDonald's four cheeseburgers and three medium fries have a total of 2290 calories. Six cheeseburgers and two medium fries have 2560 calorie

Algebra ->  Coordinate Systems and Linear Equations  -> Lessons -> SOLUTION: This is the question I need help on: At McDonald's four cheeseburgers and three medium fries have a total of 2290 calories. Six cheeseburgers and two medium fries have 2560 calorie      Log On


   

Question 845812: This is the question I need help on: At McDonald's four cheeseburgers and three medium fries have a total of 2290 calories. Six cheeseburgers and two medium fries have 2560 calories. How many calories does each item contain?
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
x = how many calories in one cheeseburger
y = how many calories in the medium serving of fries

4x%2B3y=2290 and 6x%2B2y=2560.

Multiply the second equation by 3%2F2, and then solve the system using the elimination method at least for x.


----------------Continued-------
%283%2F2%29%286x%2B2y%29=%283%2F2%29%282560%29
9x%2B3y=3840, the second equation.

Use the System As:
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9x+3y=3840
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4x+3y=2290
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Eliminating y---Subtract the "2290" equation from the "3840" equation.
%289x%2B3y%29-%284x%2B3y%29=3840-2290
9x%2B3y-4x-3y=1550
9x-4x%2B3y-3y=1550
5x=1550
x=1550%2F5=highlight%28310=x%29
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Next, using any equation you want, solve for y ...
6x+2y=2560
3x+y=1280
y=1280-3x
y=1280-3*310
y=1280-930
highlight%28y=350%29