A trick question

Number Theory Level 2

Determine all 5 digit numbers that are formed using the digits 1, 2, 3, 4, and 5, each exactly once, that is also divisible by 11.

Enter your answer as the sum of all these numbers.


The answer is 0.

King Zhang Zizhong by King Zhang Zizhong , 26, Pakistan

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2 solutions

Use the power of logic for this one. I did it and I won.

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Neerja Verma
Apr 29, 2014

SINCE NO TWO SUCH SETS OF GIVEN DIGITS CAN BE FORMED WHOSE DIFFERENCE IS ZERO, SO NO NUMBER IS POSSIBLE DIVISIBLE BY 11.

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This question fails to specify that all such 5-digit numbers must be formed by using each of the digits 1, 2, 3, 4, and 5. Otherwise, for example, we could form 11242, which is divisible by 11.

Michael Mendrin - 7 years ago

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