The cost price is $20.
The selling price is $24.
When the price of an item is marked up, it means that the price of the item has been increased.
Cost price = dollar mark up / percent dollar mark up
4/0.2 = $29
Selling price = (1.20 x 20) = $24
To learn more about percentages, please check: https://brainly.com/question/25764815
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