Question

If the sum of a number of two digits and a numbers formed by reversing the digits is 99, then what is the sum of the digits of the original number?

Answer 1

let the number at ones place be y
and the number at tens place be x

Now the number is 10x+y and the number formed by reversing its digits is 10y +x

Their sum is 10x+y+10y+x

According to question,
10x+y+10y+x=99
11x+11y=99
x+y=9

Hence the sum of the digits of the no. is
9