If the tens digit of a two digit number is subtracted from the units digit, the difference is 8. The number with the digits reversed is 10 more than 9 times the units digit of the original number.
Let the unit digit be x and the tens digit by y.
x - y = 8 or
x = y + 8
without any more information, we know that y can only be either 0 or 1, since x has to be a single digit.
if y = 0, then x = 8 and our two digit number would be 08, (not really a
2 digit number)
so y = 1, x = 9 and the original number is 19
what about our other condition?
9 times the units digit and then 10 more = 9*9 + 10 = 91
which is the original number reversed, so
our original number is 19