Question

Marcus and his friends are having

a Final Four party. Marcus buys 5
burgers and 9 sodas for $28.75 at
the Beefy Burger joint. When five
more of his friends show up, he
heads back to Beefy Burger for 10
more burgers and 10 more sodas
and spends $47.50.​

Answer 1

S = 1.25

B = 3.50

Explanation:

I assume you need to know how much a burger and how much a soda is.

Basically it's a system of equations.

5B + 9S = 28.75

10B + 10S = 47.5

There are a few ways to do this, if you like I can show another, but this is how I usually solve a normal system of equations.

First solve for one variable in one equation. I am going to choose to solve for B in 10B + 10S = 47.5

10B + 10S = 47.5 (divide the whole thing by 10)

B + S = 4.75 (subtract S from both sides)

B = 4.75 - S

Now plug this B into the other equation.

5B + 9S = 28.75

5(4.75 - S) + 9S = 28.75

23.75 - 5S + 9S = 28.75 (Now just solve for S

4S = 5

S = 5/4

S = 1.25

Now plug THIS back into the first one.

B = 4.75 - S

B = 4.75 - 1.25

B = 3.50