A bag contains red, blue, and green marbles. There are twice as many red marbles as blue ones, and half as many green marbles as blue ones. If there are 28 marbles in total, how many are blue?
8
Let blue = b. Red = 2b. Green = b/2. Total = b + 2b + b/2 = 3.5b = 28. Therefore, b = 28 / 3.5 = 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: Medium. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
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