Final answer:
After setting up and solving two equations based on the purchase transactions, the cost of one slice of pizza is found to be $1.75.
Step-by-step explanation:
To find the cost of one slice of pizza, we first need to establish two equations from the given information. We have two transactions with different quantities and total costs:
5 bottles of water and 8 slices of pizza for $20.25.
1 additional bottle of water and 3 additional slices of pizza for $6.50.
Let's use W to represent the cost of one bottle of water and P to represent the cost of one slice of pizza. From our first transaction, we can say:
5W + 8P = $20.25 ...(1)
And from the second transaction:
W + 3P = $6.50 ...(2)
Now, we can solve these equations to find the values of W and P. If we multiply equation (2) by 5, we get:
5W + 15P = $32.50 ...(3)
Then, we can subtract equation (1) from equation (3) to get:
7P = $12.25, and by dividing both sides by 7, we find that P, or the cost of one slice of pizza, is:
P = $1.75
Therefore, the cost of one slice of pizza is $1.75.