a,b and c are positive integers less than or equal to 9. If a,b and c are assembled into the six-digit number aabbcc, which of the following must be a factor of aabbcc? Choose the most appropriate option.
A) 9
B) 3
C) 7
D) 11
E) None of these
The sum of the digits in place 1,3 and 5 is a+b+c is equal to the sum of the digits in place 2,4 and 6 which is a+b+c. thus the number abcabc is divisible by 11. thus 11 must be a factor of abcabc.   Answer: 11
<result>D</result>
a,b and c are positive integers less than or equal to 9. If a,b and c are assembled into the six-digit number aabbcc, which of the following must be a factor of aabbcc?