Correct option is D
Given:
- Two numbers: 10a + b and 10b + a, where a and b are the digits.
Formula:
Difference of squares = (10a + b)2 - (10b + a)2.
Solution:
22
Expand: (10a + b) - (10b + a) = [(10a + b) + (10b + a)] × [(10a + b) - (10b + a)] = (11a + 11b) × (9a - 9b)
Factor out common terms: = 11 × 9 × (a + b) × (a - b)- Clearly, the result is always divisible by 11.
Final Answer: (d) 11


