perplexus.info :: Numbers : Duplicate Digit Determination

Duplicate Digit Determination (Posted on 2006-12-03)

If 2^P and 5^P start with the same (non-zero) digit for positive integer P, what is that digit? Can you prove it must be so?

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Subject	Author	Date
Answer	K Sengupta	2008-11-08 00:53:38
Another solution without logs	Charlie	2006-12-04 09:11:08
An easy way out	Federico Kereki	2006-12-03 17:51:41
Solution without log	JLo	2006-12-03 12:13:40
Some calculations (spoiler)	Steve Herman	2006-12-03 11:08:27
solution	Charlie	2006-12-03 11:05:20

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