Is it 6 ?

For a number to be multiple of 36 number must be divisible by 4 as well as 9.

So last digit will be 6 only.

Second last digit can not be 6 because 66 is not divisible by 4. So second last digit will be 9

1 digit numbers (None) = 0

2 digit numbers (96) = 1

3 digit numbers = 1

x96, x can be 9 only because sum of digits of 696 is not divisible by 9.

4 digit numbers (None) = 1

xx96 - Four possible values of xx - 66,69,96,99. Only 6696 has sum of digits divisible by 9.

5 digit numbers (None) = 3

xxx96 - Eight possible values for xxx

66696 - Sum of digits = 33

66996 - Sum of digits = 36 - YES

69696 - Sum of digits = 36 - YES

69996 - Sum of digits = 39

96696 - Sum of digits = 36 - YES

96996 - Sum of digits = 39

99696 - Sum of digits = 39

99996 - Sum of digits = 42

Total = 1+1+1+3 = 6

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SAID BUSINESS SCHOOL, OXFORD - MBA CLASS OF 2008