A merchant has four weights of 1 lb, 3 lb, 9 lb, and 27 lb. Using a traditional two-pan balance scale, what is the single heaviest whole-pound object she can weigh by placing weights on either one or both sides of the scale?
40 lbs
By utilizing weights on both pans, she can measure any weight up to the sum of all available weights (1 + 3 + 9 + 27 = 40 lbs) by placing the object on one side and an optimal combination of weights on either the same side or the opposite side.
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: Hard. More like this: Logic riddles with answers or try Einstein's Logic Grid for a different kind of puzzle.
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