A 3-digit padlock code follows these rules: The sum of all three digits is 17. The third digit is twice the first digit. The second digit is 2 greater than the third digit. What is the code?
386
Let the digits be A, B, and C. C = 2A and B = C + 2 = 2A + 2. The sum A + B + C = A + (2A + 2) + 2A = 5A + 2 = 17. Solving 5A + 2 = 17 gives 5A = 15, so A = 3. Then C = 6 and B = 8. The code is 386.
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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