To determine how much Sandra charges for each necklace, we can analyze the given profit equation:
\[ P = 7.5cn - (2.25n + 15) \]
Where:
- \( P \) = total profit,
- \( n \) = number of necklaces sold,
- \( c \) = cost per necklace.
From the equation, \( P \) can also be expressed as
\[ P = (price \cdot n) - (cost \cdot n + fixed costs) \]
Here, \( 7.5cn \) represents the total revenue from selling \( n \) necklaces at a price of \( 7.5 \). The term \( (2.25n + 15) \) represents the total costs, which consist of a variable cost of $2.25 per necklace \( (2.25n) \) and a fixed cost of $15.
To find how much Sandra charges for each necklace, we look at the coefficient of \( n \) in the revenue term.
The price per necklace (the revenue part) can be identified in the profit equation:
- Sales revenue per necklace = $7.50
Thus, the answer is:
B. $7.50