perplexus.info :: Just Math : Same Six Digits

Same Six Digits (Posted on 2014-03-26)

What are the possible values of a six digit positive integer N, where all digits of N are different, and 4*N has the same six digits as N?

Prove that there are no others.

See The Solution Submitted by K Sengupta

Rating: 5.0000 (1 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)

re: Let Me REcount the ways

| Comment 5 of 6 |

(In reply to Let me count the ways by Steve Herman)

Let Me REcount the ways:

.....So at first glance we have 12*8*7*6*5 = 20,160 possibilities.

But the number must equal 0 OR 3 OR 6 mod 9, because N and 4N have the same digits.

And approximately 1/3 of the 20,160 possibilities meet this criteria.

So I guess that there are only 6720 viable candidates for N...

see the sod of Charlie's numbers" :18,21,27 etc.

Posted by Ady TZIDON on 2014-03-26 13:42:26

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