Question

Bob took his family out to lunch. He bought 3 hot dogs and 2 hamburgers for $11. If the guy in front of him bought 2 hot dogs and 4 hamburgers for $16, what is the cost of one hamburger?

Answer 1

Hotdog: $1.50

Hamburger: $3.25

Explanation:

You write down the 2 equations based off of the information as I did:

Let x = cost of a hotdog

Let y = cost of a hamburger

and so:

3x + 2y = 11

2x + 4y = 16

Now, we need to find x and y:

We will make both equations equal to y to compare them to each other.

2y = 11 - 3x

y = 5.5 - 1.5x

4y = 16 - 2x

y = 4 - 0.5x

4 - 0.5x = 5.5 - 1.5x

x = $1.5

Now plugging in x into the equation:

2(1.5) + 4y = 16

3 + 4y = 16

4y = 13

y = $3.25

And so hotdog = $1.5 and hamburger = $3.25