Question

The sum of two digit no and no obtained by interchanging its digits is 99 .find the no

Answer 1

HEYA MATE HERE IS YOUR ANSWER.....

Let  a  and  b be the digits of your number  n,  so that  

n = 10a + b.

The number after reversing digits is  10b + a.

Then from the condition you have the system of two equations for the unknowns  a  and  b: .

a + b = 9

(10a+b) + (10b + a) = 99

Now,  simplify it: .

a + b = 9

11a + 11b = 99

Simplify it one more time:

a + b = 9

b+ a = 9

So, you have, actually, only ONE equation for the digits and do not have any additional info. Therefore, the answer is not unique. All the numbers 18, 27, 36, 45, 54, 63, 72, 81 are the solutions.

Answer 2

hope you will understand my answer