Answer:
Shoes with discount = $17
Necklace = Price * 0.85
Explanation:
-If the tennis shoes store sells other things than shoes-
Shoes = $20.00
Discount = 15%
*Price expressed as a percentage*
Price without discount = 100%
Price after discount = 100% - 15%
Price after discount = 85%
*Normal price*
Price without discount = 20
Price after discount = 20 * 0.85
Price after discount = 17