Answer:
$20.63 if you tip on the pre-tax amount
Explanation:
You pay $12.99 for the pizza, plus the 8% tax on the pizza, plus the 20% tip of the cost of the pizza, so if you tip on the pre-tax amount, you pay
$12.99(0.08) = $1.04 in sales tax
$12.99(0.2) = $2.60 for the tip
and $4 delivery charge,
so you pay a total of
$12.99 + $1.04 + $2.60 + $4 = $20.63