So for this, you will be doing a system of equations. The first equation will be how much you spent and the second equation is how much they advertise.
Let h = cost of hotdog and d = cost of drinks
![10h+5d=35\\ 7h+4d=25.25](https://tex.z-dn.net/?f=%2010h%2B5d%3D35%5C%5C%207h%2B4d%3D25.25%20)
With this, i'll be using the substitution method. So firstly, subtract 10h on each side of the first equation. It will look like this: ![5d=35-10h](https://tex.z-dn.net/?f=%205d%3D35-10h%20)
Next, divide 5 on each side of the first equation. Your answer will be ![d=7-2h](https://tex.z-dn.net/?f=%20d%3D7-2h%20)
Next, replace d in the second equation with (7-2h). Your second equation will look like this:
. From here you can solve for h.
Firstly, foil 4(7-2h). ![7h+28-8h=25.25](https://tex.z-dn.net/?f=%207h%2B28-8h%3D25.25%20)
Next, combine like terms: ![28-h=25.25](https://tex.z-dn.net/?f=%2028-h%3D25.25%20)
Next, subtract 28 on each side to get ![-h=-2.75](https://tex.z-dn.net/?f=%20-h%3D-2.75%20)
Lastly, multiply -1 on each side of the equation to get ![h=2.75](https://tex.z-dn.net/?f=%20h%3D2.75%20)
Now that we got h, we can solve for d by substituting 2.75 in the h variable in either equation. For this, I'll be using the first one.
![10(2.75)+5d=35\\ 27.5+5d=35\\ 5d=7.5\\ d=1.5](https://tex.z-dn.net/?f=%2010%282.75%29%2B5d%3D35%5C%5C%2027.5%2B5d%3D35%5C%5C%205d%3D7.5%5C%5C%20d%3D1.5%20)
In short, hotdogs are $2.75 each and drinks are $1.50 each.