Question

The sum of two digit number is 12 the number obtained interchanging its exceed the given number by 18 find the number

Answer 1

This is your answer see this

Answer 2

lets the two digit number be x and y where x in 10 place and y in once ( 10x + y )
ATQ
•CASE 1 : the sum of two digit is 12
x + y = 12-----(1)

•CASE 2: the no. obtained interchanging its exceed the given no. (10x + y ) by 18
10y + x = 10x +y + 18
9y-9x = 18
9 (-x+y) = 18
-x + y = 2-----(2)

on adding 1 and 2
you will get value