Two mixtures of coffee beans in one-pound bags. A store is selling
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?