Question 694692
The sum of the digits of a two-digit number is 12.
 let the ones digit is x then tens digit is 12-x
 then the no is 10(12-x)+x........original no
 If the digits are reversed, 
 the no is 10x+(12-x)...........new no
 the new number is 18 less than the original number.
 so 10x+(12-x)=10(12-x)+x-18
 or 9x+12=102-9x
 or 18x=102-12=90
 or x=5 is the ones digit 
 so the tens digit ig 12-5=7
 so the original number is 75