Question

Sum of the digits of a two digit number is 9. When we interchange the digits, it is found that the resulting new number is 9 more than the original number. Find the 2 digit number.

Answer 1

Answer:

sum of two digit no. =9,1st d=x,2nd d=y

no. formulae=10x+y

reversing no. =10y+x

x+y=9......(1)

acc. to que.

10y+x=10x+y+9

9y-9x=9,y-x=1....(2)

from(2) we have

y=1+x

put y =1+x in eq. (1)x

x+1+x=9

2x=8

x=4

y=1+4=5

Answer 2

Let the number be 10x + y

x+y = 9

10x + y + 9 = 10y +x

x-y = -1

On adding we get x = 4

Y = 5

So, the number is 10 x + Y is equal to 45