Math problem,total cost question!?

Question

You are creating a flower arrangement for a friend. The total cost(in dollars) for one vase and f flowers is given by the expression 8+2.5f. How much will it cost to make an arrangement with 8 flowers.

I added 8+2.5 and came up with $10.5... do i multiply that with 8? or is 10.5 my answer?

Answer 1

8 + 2.5f

8 + 2.5(8)

8 + 20

$28

Answer 2

$28

8+2.5(8)=$28