In a secure facility, a password must be formed using four distinct non-zero digits. The second digit is double the first. The third digit is the sum of the first two. The fourth digit is the difference between the third and the first. What is the password?
1232
Let the first digit be 1. The second is double that (2). The third is their sum (1 + 2 = 3). The fourth is the third minus the first (3 - 1 = 2). Putting it together yields 1232.
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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