A store is selling two mixtures of coffee beans in one-pound bags. The first mixture has 12 ounces of Sumatra combined with 4 ounces of Celebes Kalossi, and costs $15. The second mixture has 4 ounces of Sumatra and 12 ounces of Celebes Kalossi, and costs $21. How much does one ounce of Sumatra and one ounce of Celebes Kalossi cost?

Question

Select one:
a. $1.65 for Sumatra and $1.20 for Celebes Kalossi
b. $0.75 for Sumatra and $1.50 for Celebes Kalossi
c. There is no solution.
d. $1.50 for Sumatra and $0.75 for Celebes Kalossi

Answer 1

12s+4c = 15
4s+12c = 21

now just solve for s and c.