Question

The sum of two no is 9.If 9 is added to this no.,the digits get interchanged.What is the no. Ineed the procedure

Answer 1

let the tens place be x and once place be y
original no=10x+y
reversed no =10y++
acc. to question ,
x+y=9 ------(1) | from (1)
9+10x+y=10y+x | x=9-y-----(3)
=> 9+10x-x+y-10y=0 | substituting (3) in(2)
=9+9x-9y=0 | 9-y-y=-1
=9 (x-y)=-9¤ | 9+1=2y
x-y=-9/9 | 2y=10
x-y= -1 ----(2) | y=5
y=5 in (3)
x=9-5=4
therefore the original number is 45