Let the digit at unit’s place be a and ten’s place be b. Thus, the number to be found is .
From given question, the sum of two digit number is equal to .
Thus we can write equation according to question,
………….. (i)
On interchanging the place of digits, the new number so formed will be .
It is also given in question that, the new number obtained after interchanging the digits is greater by from the original number.
Therefore, this can be written as;
⇒
⇒
⇒
⇒ ………………. (ii)
On solving (i) and (ii), we get value of a and b
Adding the eq. (i) and (ii), we get;
⇒
⇒
⇒
⇒
Putting the value of a in the equation (i), we get;
⇒
⇒
Thus, the required number is