Each of A, B and C is a different digit among 1 to 9. How many different values of the sum of A, B and C are possible, if ABA X AA = ACCA ?
Step-by-step Solution:
The equation is ABA * AA = ACCA. The last digit of the product is determined by the last digits of the numbers being multiplied. Here, the last digit of (A * A) must be A.
We can test the digits from 1 to 9 to see which ones satisfy this condition:
1 * 1 = 1 (A=1 is possible)5 * 5 = 25 (A=5 is possible)6 * 6 = 36 (A=6 is possible)So, A can only be 1, 5, or 6.
5B5 * 55 = 5CC5. The result of 500+ * 55 will be a 5-digit number, but 5CC5 is a 4-digit number. This is impossible.6B6 * 66 = 6CC6. The result will also be a 5-digit number. This is also impossible.Therefore, the only possibility is A = 1.
The equation becomes 1B1 * 11 = 1CC1. We can express this algebraically:
(101 + 10*B) * 11 = 1001 + 110*C 1111 + 110*B = 1001 + 110*C 110 + 110*B = 110*C Dividing the entire equation by 110 gives us the simple relationship: 1 + B = C.
We need to find pairs of B and C where C = B + 1, and A, B, and C are all different digits from 1 to 9. Since A=1, B cannot be 1.
Conclusion: The possible values for the sum (A+B+C) are {6, 8, 10, 12, 14, 16, 18}. These are 7 different, unique values.
Final Answer: The correct option is C. 7.