Let's write an equation to solve this pronlem.
First off, let's let x be the tens digit and the other be y.
From the first of the problem, we have the equation
10x+y=10y+x+72
From the second part of the problem, we have the equation
x=2y−1
Solving this system, we get that x=17,y=9
This equation cannot be satisfied.
From the first equation, we have that y=x−8
There are only two possibilities. One is where x is 9 and y is 1, so we have 91.
The other possibility is x is 8 and y is 0.
Neither of these satisfy the conditions given.
Thanks! :)