Question

At the fast food restaurant, four cheeseburgers and five small fries have a total of 2,310 calories. Three cheeseburgers and two small fries have a total of 1,330 calories. How many calories does each item contain?

Answer 1

Answer: 290 calories in a cheeseburger and 230 calories in fries.

x = calories in a cheeseburger

y =  calories in an order of small fries

Four cheeseburgers and five small fries have 2,310 calories. Therefore

4x + 5y = 2310       (1)

Three cheeseburgers and two small fries have 1,330 calories. Therefore

3x + 2y = 1330        (2)

Equations (1) and (2) model the given situation.

To solve, multiply (1) by 2, and multiply (2) by 5 to obtain

 8x + 10y = 4620          (3)

15x + 10y = 6650          (4)

Subtract (3) from (4).

7x = 2030

x = 290

From (1), obtain

5y = 2310 - 4*290 = 1150

y = 230

x = 290, y = 23

Hope this helps!

:)