A coffee shop blends a 8-per-pound coffee with a 14-per-pound coffee to create 20 pounds of a blend costing 11 per pound. How many pounds…

Let $b$ be the pounds of the $14 coffee, so $20 - b$ pounds of the $8 coffee. The total cost of the blend is $8(20 - b) + 14b = 11(20)$. Simplify: $160 - 8b + 14b = 220$, so $6b = 60$ and $b = 10$, choice C. Sanity check: $11 is exactly halfway between $8 and $14, so the two coffees are used in equal amounts. Choice A (12) and choice B (8) give prices of $11.60 and $10.40. Choice D (15) gives a blend costing $12.50 per pound. Check the weighted price.