Answer:
Molly will pay $13.20 for the dress
40% of $20 is the discount, $8.00
Step-by-step explanation:
multiply dress cost by % you will pay, then add 10%
$20 x .60 then add 10%
$12 is dress with coupon, and 10% of that is $1.20
$12 + $1.20 is $13.20