original :
unit digit --- x
tens digit --- y
then number is 10y + x and x+y=9
number reversed = 10x + y
10x+y - (10y+x) = 63
9x - 9y = 63
x - y = 7 , add this to x+y = 9
2x = 16
x = 8, then y = 1
Now put all that together.
The sum of the digits of a two digit number is 9. If the digits are reversed, the number is 63 more than the original. Find the number
1 answer