AB
+BA
-----------
AAC
In the correctly worked addition problem shown here, where the sum of the two-digit positive integers AB and BA is the three-digit integer AAC, and A, B, and C are different digits, what is the units digit of the integer AAC?	Choose the correct choice from the following answers.
A) 9
B) 6
C) 3
D) 0
E) 2
AB+BA = AAC -&gt; EQ 1   EQ 1 IMPLIES: B+A = 10+C - EQ 2 (DIFFICULT TO INTERPRET. I AGREE. JUST SUM UP THE UNITS 0IGIT IN EQ 1)   NOW SPLIT UP EQ 1   10A+B+10B+A = 100A+10A+C - EQ 3   EQ 3 IMPLIES: 11(A+B) = 110A+C   SUBSTITUTE EQ 2 (B+A = 10+C) IN ABOVE   11(10+C) = 110A+C =&gt; 110+11C = 110A + C   IMPLIES A = 1C = 0   0
<result>D</result>
AB
+BA
-----------
AAC
In the correctly worked addition problem shown here, where the sum of the two-digit positive integers AB and BA is the three-digit integer AAC, and A, B, and C are different digits, what is the units digit of the integer AAC?