If n is a 9-digit positive integer, all of whose digits are the same, which of the following must be true?
I. n is divisible by 3
II. n is divisible by 9
III. n is divisible by 10 Choose the correct answer:  A) I and II only  B) I only  C) I and III only  D) II and III only  E) I, II and III
Rule for divisibility by 3: The sum of the digits of the number should be multiple of 3   Rule for divisibility by 9: The sum of the nos digits of the number should be divisible by 9 or the number should be divisible by 3 two times.   Rules for divisibility by 9: The sum of the digits should a multiple of 9   Consider no 11111111...9 times = The sum 9*1=27----&gt; divisbible by 3,9   consider number to be 222....9 times, then sum of the no. 9*2=18 divisible by 3,9   So why so because when you sum the numbers either you can add the digits 9 times or multiply the digit *9..   Note that since 9 is divisble by 9 and 3 and thus the sum of the nos will be divisible by all the nos.   I and II only
<result>A</result>
If n is a 9-digit positive integer, all of whose digits are the same, which of the following must be true?
I. n is divisible by 3
II. n is divisible by 9
III. n is divisible by 10