a,b and c are positive integers less than or equal to 9 and multiple of 3. If a,b and c are assembled into the three-digit number abcabc, which of the following must be a factor of abcabc?	Pick one
A) 6	B) 4	C) 7	D) 5	E) 9
as a, b and c are multiple of 3, they can be written as a=3l, b=3m and c=3n. the sum of digits of abc is a+b+c = 3(l+m+n+l+m+n)=6(l+m+n).   Thus, 6 is always a factor.   6nswer: 6
<result>A</result>
a,b and c are positive integers less than or equal to 9 and multiple of 3. If a,b and c are assembled into the three-digit number abcabc, which of the following must be a factor of abcabc?