Question

A fast food restaurant sells burgers and fries.

One customer buys 3 burgers and 2 fries, and pays 7.15.
Another customer buys 4 burgers and 3 fries, and pays 9.93.
How much to Burgers and Fries cost EACH?

Answer 1

Hello!

You first make two equations

Let x stand for the price of a burger
Let y stand for the price of fries

3x + 2y = 7.15
4x + 3y = 9.93

multiply the top equation by 3 and the bottom equation by 2

9x + 6y = 21.45
8x + 6y = 19.86

You can subtract the two equations

x = 1.59

Now you can put x into one of the original equations

3(1.59) + 2y = 7.15

Combine like terms

4.77 + 2y = 7.15

Subtract 4.77 from both sides

2y = 2.38

Divide both sides by 2

y = 1.19

The answers are a burger cost $1.59 and Fries cost $1.19

Hope this helps!