Question 694688
The sum of the digits of a two-digit number is 9.
 let the ones digit is x then tens digit is 9-x
 then the no is 10(9-x)+x........original no
 If the digits are reversed, 
 the no is 10x+(9-x)...........new no
 the new number is 63 greater than the original number.
 so 10x+(9-x)=63+10(9-x)+x
 or 9x+9=153-9x
 or 18x=153-9=144
 or x=8 is the ones digit 
 so the tens digit ig 10-8=1
 so the original number is 18