To solve this problem you must apply the proccedure below:
1. Let's call:
x: hot dogs.
y: hamburguers.
2. Then, you must make a system of equations, as below:
5x+4y=12.25 (i)
4x+5y=12.50 (ii)
3. Now, you can solve the system of equation as below:
5x+4y=12.25
x=(12.25-4y)/5
4x+5y=12.50
4((12.25-4y)/5)+5y=12.50
y=1.5
4x+5y=12.50
4x+5(1.5)=12.50
x=1.25
4. Therefore, the answer is:
The cost of one hot dog is $1.25 and the cost of one hamburguer is $1.50