Question 624491
Let the first digit be x and the second digit be y.
then by question,

  x + y = 9
=> y = 9 - x  ------- eq 1

Again,
Since the number  is 10x+y when it is revered then the number becomes 10y + x.

Therefore, we get by question
=> 10x + y -(10y + x) = 45
=> 10x + y - 10y - x = 45
=> 9x -9y = 45
=> x - y = 5
=> x = 5+y
=> x = 5 + (9-x) -----frm eq 1
=> x = 5 + 9 - x
=> 2x = 14
=> x = 7

Now, eq 1
   y = 9 - x
=> y = 9 - 7
=> y = 2

Therefore the number is 72