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## Discussion of Problem 1887. Frequent Flyer Card

I probably didn't understand the problem statement correctly. does the notation on the formula really mean product?
I calculated probability of appearance of digit 0~9 as last digit and for first sample:
0: 0.925...
1: 0.009...
2~9: 0.008...
and expectation: 344.0203...

However, if i set probability from 0~9: all 0.1
the expectation becomes correct: 29.2896825397

I probably am missing something or misinterpreted something. Please, help me someone.

[AC]
[Code Deleted]

Edited by author 01.11.2011 10:19

Edited by author 01.11.2011 13:10

Edited by author 01.11.2011 13:25
Re: I probably didn't understand the problem statement correctly. does the notation on the formula really mean product?
When you have two modulo operations, you cannot just apply each of them on each step. You can take everything modulo 11 on each step, but only the last result may be taken modulo 10. If you fix it, you will get equal probabilities.
P.S. hide your code - let other people solve this problem themselves.
Re: I probably didn't understand the problem statement correctly. does the notation on the formula really mean product?