Find cost of 1 necklace:
20 necklaces = $500
1 necklace = $500 ÷ 20 = $25
Find Sales of 3/4 of the necklaces:
3/4 of 20 = 3/4 x 20 = 15 necklaces
15 necklaces sold at $40 each = 15 x 40 = $600
Find Sales of the remaining necklaces:
20 - 15 = 5
5 necklaces sold at $25 = 5 x 25 = $125
Find profit:
Total Sales = $600 + $ 125 = $ 725
Total profit made = $725 - $500 = $225
Answer: She made $225