The sum of a two-digit number is 12. the number formed by interchanging the digits is 54 more than the original number. what is the original number

39

sum of 2 digit no. can be

3+9

4+8

5+7

6+6 (which cannot be the ans since interchanging the digits would give 0 difference)

so,

93-39=54

84-48=36

75-57=18

so 93 is the reversed no. and 39 is the original no.