Question

A coffee blend contains Sumatra beans that cost $5/lb and Kona beans that cost $13/lb. If the blend costs $10/lb, how much of each type of coffee is in 50 lb of the blend?

22.5 lb of Sumatra beans and 27.5 lb of Kona beans
18.75 lb of Sumatra beans and 31.25 lb of Kona beans
20 lb of Sumatra beans and 30 lb of Kona beans
25 lb of Sumatra beans and 25 lb of Kona beans