Verified Answer :

The measurements are there to confuse you. This problem is just asking:

"What is 8 3.5?"

So let's break this down:
8 
 3 = 24
8 0.5 = 4
24 + 4 = 28

Therefore, 8lb
$3.50/lb = $28

Cool? Cool.

8 lb* ($3.50/ 1 lb)= $28

The final answer is $28~