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Two Digit Integers (Posted on 2006-07-14) Difficulty: 4 of 5
Find all possible two digit positive integers N for which the sum of digits of 10N - N is divisible by 170.

See The Solution Submitted by K Sengupta    
Rating: 3.0000 (2 votes)

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re(2): Solution | Comment 6 of 11 |
(In reply to re: Solution by Patrick)


You need to add up the digits of 10^N - N, and that number is what must be divisible by 170.

For example, 10^39 - 39 is 37 9's followed by 61, and the digits of that number add up to 37*9+6+1=333+7=340=2*170.


  Posted by Richard on 2006-07-18 23:06:36

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