A master lock has a three-digit code. The sum of the first and second digits is 8. The sum of the second and third digits is 14. The sum of all three digits is 17. What is the code?
3, 5, 9
Let the digits be A, B, and C. We know A + B + C = 17. Since A + B = 8, substituting this into the total gives 8 + C = 17, so C = 9. Since B + C = 14, substituting C = 9 gives B + 9 = 14, so B = 5. Since A + B = 8, substituting B = 5 gives A + 5 = 8, so A = 3. The code is 359.
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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