Difficulty: Fun
Alice forgot the code to get into her computer. She knows it was a number with three digits.
All she can remember is that the first digit is the second digit minus 3. The second digit is 4 times the third digit. And two of the digits are the same.
Can you help Alice get into her computer?
Need a hint?
Remember that a three-digit number looks like 123 or 285 or 904.
The third digit of Alice’s code has to be quite small for it to be multiplied by 4 and not become a two-digit number itself.
Brainteaser answer
The code to Alice’s computer is 141.
It might be hard to know where to start, but the fact that all three numbers are single-digits tells us a lot. That’s because the third digit would need to be small enough that multiplying it by 4 still gives a single-digit answer. For example, even a small number like 3 multiplied by 4 makes 12, a two-digit number.
So, the third digit can only be either 1 or 2. If it’s 2, the second digit is 8. That means the first digit would be 8 – 3, which is 5. These are all single-digit numbers, but we don’t satisfy the last clue about two digits being the same.
If the third digit is 1, however, the second digit is 4. The first digit would then be 4 – 3, which is also 1. This satisfies the last clue about two digits being the same. 141 is our answer!
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