A candy store sells two types of chocolates: dark chocolate for $12 per pound and milk chocolate for $8 per pound. If a customer buys a 5-pound mix of these chocolates for a total of $50, how many pounds of dark chocolate did the customer buy?
✓ Correct Answer: Option B
Let D be pounds of dark chocolate and M be pounds of milk chocolate. D + M = 5 and 12D + 8M = 50. From the first equation, M = 5 - D. Substitute: 12D + 8(5 - D) = 50. 12D + 40 - 8D = 50. 4D = 10. D = 2.5 pounds.