Rana thinks of a two digits number.
When the number is multiplied with itself answer is 144.
When the digits swap their places, the new number so formed when is multiplied with itself answer is 441.
What number is he thinking about?

Answer: D. 12

D. 12
The square root of 144 is 12 (12 × 12 = 144).
When you swap the digits of 12, you get 21.
The square of 21 is 441 (21 × 21 = 441).
Therefore, the original number is 12.

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