Question 32104
Let the number be 10x+y
x+y=10;
10x+y-72=10y+x
=>9x-9y=72
=>x-y=8;
We need to solve for x and y from the following equations:
x+y=10
x-y=8
Adding above:
2x=18
=>x=9
y=10-x=1
So, the original number is 91