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I am in a puzzle that which is generated by one of my friend .

She gave me last 4 numbers of her mobile phone & i want to find the first 6 numbers.

I guessed the first 4 letters.

Assume that AAAA is the first 4 letters and MMMM is the last 4 letters and XX is the 2 letters after the first 4 letters .

So her number is 10 digit soit would be AAAAXXMMMM

I know AAAA and MMMM and now i have to find XX .

I know getting the exact value is impossible but i think that i can get the combinations of XX [2 digits].

How can i get this ?

Thank you.

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closed as not a real question by Paul, Aaron, Leonid Kovalev, Asaf Karagila, t.b. Aug 18 '12 at 9:37

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

up vote 0 down vote accepted

You should apply formula of permutations with repetition .

So , number of permutations in this particular case is given by :


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ok how can i calculate this ? – Red Jan 22 '12 at 8:45
@DileepDil,You can only calculate number of possible solutions which is $100$ – pedja Jan 22 '12 at 8:50
yeah,i am really poor in maths..i need the combinations...not 100. – Red Jan 22 '12 at 8:55
@DileepDil,Then write them all..$00,01,02...$ , etc . – pedja Jan 22 '12 at 9:00
Pardon me if i am making some troubles,but is there any calculator or something that which i can generate those numbers ? – Red Jan 22 '12 at 9:01

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