Answer :

Materials = $4.25
Labor = $5.35
Sale Price = $16.99

A.)  Profit = Sale Price - (Materials + Labor)
      Profit = 16.99 - (4.25 + 5.35)
      Profit = 16.99 - (9.60)
      Profit = $7.39

      Profit / Sale Price = % Profit
      7.39 / 16.99
             or
       739 / 1699

B.)  % Profit = Profit / Sale Price × 100
      % Profit = 7.39 / 16.99 × 100
      % Profit = 0.43496 × 100
      % Profit = 43.496 %
      % Profit = 43 %

C.)  Total Sales = $324.86

       Necklaces Sold = Total Sales / Individual Sale Price
       Necklaces Sold = 324.86 / 16.99
       Necklaces Sold = 19.12 

**This question is absolutely ridiculous because either she made money from tips or someone either paid too much or too little**

       Total Profit = Necklaces Sold × [Sale Price - (Materials + Labor)]
       Total Profit = 19 × [16.99 - (4.25 + 5.35)]
       Total Profit = 19 × (7.39)
       Total Profit = $140.41

               OR

       Total Profit = 20 × (7.39)
       Total Profit = $147.80