Question

the sum of a two digit number and the number obtained by reversing the order of its digits is 121
If the digit in unit's and ten's place are in X and Y respectively.

Answer 1

10y + x + 10x + y = 121

11x + 11y =121

I guess the rest of the question is incomplete.. please check

Answer 2

Let the digit in unit’s place be x

and the digit in ten’s place be y

then the two digit number = 10y + x

and the number obtained by reversing the digits

= 10x + y

as per the given condition

(10y + x) +(10x + y) = 121

11x +11y = 121

11(x + y) = 121

x + y = 11

∴ x + y - 11= 0