The digit in ones place of a number is twice the digit in its tens place. if 9 is added to the number, the digit of the sum of obtained are reverse of those of the number find the number
The answer is 12. The digit 2 is 2 times more than 1, so it matches the first part. 12 + 9 = 21. If you switch the digits of 12 around, you will get 21. So the answer is 12.
