Answer:
So first you do $0.50 x 3 = 1.5
then you add that to $12.00
$12.00 + 1.5 = 13.5
13.5 is the cost of one pizza.
Since they bought 12:
The total cost of the 12 pizza is $162 <== not important
13.5 divided by 8 is 1.687
round 1.56875 to the nearest cent 1.7 = $2
so each slice costs $2