Question

Big Mack buys meat for the family reunion cookout. He needs to buy 11 packagesof meat. A package of hotdogs costs $2.59, and a package of hamburgers costs$5.29. he spent a total of $39.29. How many hamburger packages were bought? (

Answer 1

Hello!

Let's write some important information contained in the exercise:

• hotdogs: $2.59 (,x,)

,

• hamburgers: $5.29 (,y,)

He needs 11 packages. Let's write it:

• x + y = 11

He spent a total of $39.29. We can write it as:

• 2.59x + 5.29y = 39.29

Now, let's solve these two equations as a linear system:

$\begin{cases}x+y=11\text{ equation A} \\ 2.59x+5.29y=39.29\text{ equation B}\end{cases}$

First, let's isolate x in equation A:

$\begin{gathered} x+y=11 \\ x=11-y \end{gathered}$

Now, we will replace where's x by 11-y in equation B:

$\begin{gathered} 2.59x+5.29y=39.29 \\ 2.59(11-y)+5.29y=39.29 \\ 28.49-2.59y+5.29y=39.29 \\ -2.59y+5.29y=39.29-28.49 \\ 2.7y=10.8 \\ y=\frac{10.8}{2.7} \\ \\ y=4 \end{gathered}$

As I called the hamburgers as 'y', we know that he bought 4 packages of hamburgers.