Three boxes contain marbles. Box A has twice as many as Box B. Box C has 5 more than Box A. If there are 45 marbles in total across all three boxes, how many are in Box B?
8
Let B = x. Then A = 2x, and C = 2x + 5. Total = x + 2x + (2x + 5) = 45 -> 5x + 5 = 45 -> 5x = 40 -> x = 8.
About this riddle
Math riddles hide a calculation inside a short story. Pull out the numbers, work out what is being asked, and watch for a trick such as a unit change.
Difficulty: Easy. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
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