perplexus.info :: Just Math : Getting The Minimum With SOD

Getting The Minimum With SOD (Posted on 2008-12-02)

Determine the minimum value of a positive decimal integer m such that:

SOD(m) = 100, and: SOD(2m) = 110

where, SOD(x) denotes the sum of the digits of x.

Note: Try to derive a non computer-assisted method, although computer program/spreadsheet solutions are welcome.

See The Solution Submitted by K Sengupta

Rating: 4.5000 (2 votes)

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Solution

Comment 2 of 2 |

SOD(2,449,999,999,999) = 100
SOD(2 x 2,449,999,999,999) = SOD(4,899,999,999,998) = 110

Posted by Dej Mar on 2008-12-02 21:22:04

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