be the unit digit and y
be tens digit.
Then the original number be 10x+y.
Value of the number with reversed digits is 10y+x.
As per question, we have
If the digits are reversed, the digits is greater than the original number by 18.
Multiply equation (1) by 9, we get
Add equations (2)and (3),
Substitute this value in equation (1), we get
Therefore, the original number is 10x+y=10×5+7=57..