A merchant mixes two types of coffee beans. Bean A costs $4 per pound, and Bean B costs $7 per pound. She creates a 10-pound bag that costs $5.20 per pound on average. How many pounds of Bean B did she use?
4 pounds
Let x be pounds of Bean B. Then 10 - x is pounds of Bean A. Total cost equation: 4(10 - x) + 7x = 5.20 * 10. 40 - 4x + 7x = 52. 3x = 12, so x = 4.
About this riddle
Logic riddles give you a few facts and ask what must be true. List what you know, cross out what cannot be, and see what is left.
Difficulty: Medium. More like this: Logic riddles with answers or try Einstein's Logic Grid for a different kind of puzzle.
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