Answer: List price = $99.55
Trade Discount = 80%
Step-by-step explanation:
Let the complement be represented by x
Trade discount will then be = 4x
Complement + Trade Discount = 100%
x + 4x = 100%
5x = 100%
x = 100%/5
x = 20%
Complement = 20%
Trade Discount = 4x = 4 × 20% = 80%
List price = Net price / Complement of trade discount.
= $19.99 / 20%
= $19.99 / 0.2
= $99.95