Final answer:
The expression for the cost would be (1/4)P + $2.50.
Step-by-step explanation:
The question is asking for the cost of something that is $2.50 more than one-fourth the cost of a pizza. Let's represent the cost of a pizza as 'P'. One-fourth the cost of a pizza is (1/4)P. To find $2.50 more than that, we can add $2.50 to (1/4)P. So, the expression for the cost would be (1/4)P + $2.50.