Number Format  17 Aug 2009
Find the number of the form
X1X2X3X4X5X6X7X8
I hope I had the coffee correctly today 
Re: Number Format  17 Aug 2009
72185634 :d

Re: Number Format  17 Aug 2009
Nice question and nice reply too :)
hoping this is correct, Congrats Saswat ;) 
Re: Number Format  17 Aug 2009
Explanation :
Let us consider (for clarity), the number to be PQRSTUVW. So, ST must be divisible by 5. > As no zero is allowed only possibility is T = 5. > U must be 2 or 6 as TU is divisible by 4. Now, PQ must be divisible by 8, and QR by 7. > PQ can be 16, 24, 32, 48, 64, 72. > QR can be 14, 21, 28, 42, 63. > Clearly, PQR can be 163 or 321 or 328 or 721 or 728. > Corresponding possible values of PQRS for above PQR values are : 1636, 3218, 3284, 7218, 7284. > Clearly 1636 is impossible, 'coz of repetition of 6. So, we are left with the following values of PQRSTU yet : 321856, 328456, 721856, 728456. Now, UV is divisible by 3. As, U can only be 6 (as seen from above list), only 63 is the possible case. So, we can reduce the possible set to : 7218563, 7284563 now. The only thing we are to do now is to make the number even, by adding a digit at the right. We can add only 2, 4, 8 or 6. In the first case, we can use only 4, 'coz all others are used up. In the second, we cannot use any of them, so it can be rejected. We are finally, left with 72185634. 
Re: Number Format  17 Aug 2009
Great

Re: Number Format  17 Aug 2009
Thanx :)

Re: Number Format  17 Aug 2009
well done saswat...

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