Question

if a number consists of two digits whose sum is 9 if 27 is subtracted from the number is digits are reversed find the number

Answer 1

let the unit place digit of number be y and the tenth place digit be x
according to question x+y=9
also 10x +y -27 = 10y +x
by solving both the equation x=6 and y=3
and the number is 63

Answer 2

Let the digits of the number be a and b
Sum of the digits= (a+b)= 9. Equation 1
Original Number= (10a+b)
If 27 is subtracted from the number, it's digits are reversed, so
(10a+b)-27= (10b+a)
(9a-9b)= 27
(a-b)= 27/9= 3. Equation 2
On subtracting, Equation 2 from Equation 1
b= 3
a= 6
Original number= (10a+b)= (10*6+3)= 63
ANS= 63