Question

The sum of the digits of a two digit number is 9. again nine times this number is twice the number obtained by reversing the order of digits then the number is

Answer 1

Let the digits be x and y.
No =10x +y
X+y=9
9 (10x +y)=2(10 y+x)

Answer 2

Hi !

Let the no:s in ten's place be "x" and the no: in unit's place be"y"
Then the original no: is 10x + y

Given ,
x + y = 9                             ----> (1)

Reversed order of no:s ,:-
10y + x is the reversed no:

so , given :-

9(10x + y) = 2(10y+x)
90x + 9y = 20y + 2x
88x - 11y = 0
11 [ 8x - y) = 0
8x - y = 0                ----> (2)

(2)+ (1)

  8x - y = 0
+ x + y = 9
---------------
9x = 9
x = 1

x + y = 9
1 + y = 9
y = 9 - 1
y = 8

=============================

The no: is 10x + y

10 (1) + 8
= 18

18 is the no: