Final answer:
The selling price for each of the 4 cups is approximately $4.31, and the profit made on each cup is approximately $1.81 after a 15% profit margin.
Step-by-step explanation:
The student initially bought 6 cups for $15 and sold 4 cups after a 15% profit. To calculate the selling price per cup and the profit made on each of the cups sold, we first need to determine the total selling price for the 4 cups. If the student made a 15% profit on the sale of the 4 cups, we can represent the total cost of the 6 cups as the original investment (C), where C = $15.
To find the total revenue (R) after gaining a 15% profit, we use R = C + 0.15C. Substituting C with $15 gives us R = $15 + 0.15 x $15, which simplifies to R = $15 + $2.25, hence R = $17.25. Since this is the revenue from 4 cups, we divide this by 4 to get the selling price per cup: $17.25 / 4 = $4.31 approximately.
To calculate the profit made per cup, subtract the original cost per cup from the selling price per cup. The original cost per cup is $15 / 6 = $2.50. The profit per cup, therefore, is $4.31 - $2.50 = $1.81 approximately.