perplexus.info :: Just Math : The Last Two Digits

The Last Two Digits (Posted on 2013-09-04)

What are the last two digits of (1+5^(2n+1))/6?
Note that n is assumed to be any positive integer.

No Solution Yet Submitted by Danish Ahmed Khan

Rating: 4.0000 (1 votes)

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re: answer - spoiler

Comment 3 of 3 |

(In reply to answer - spoiler by Ady TZIDON)

All powers of 5 greater than 25 end in 125 or 625. The odd powers of 5 end in 125, and the even powers of 5 end in 625.

Posted by Math Man on 2013-09-28 21:52:11

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