Question

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

Answer 1

Given units digit is x and tens digit is y

Hence the two digit number = 10y + x

Number obtained by reversing the digits = 10x + y

Given that sum of a two digit number and the number obtained by reversing the order of its digits is 121.

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

$\Rightarrow 10y+x+10x+y=121$

$\Rightarrow 11x+11y=121$

$\Rightarrow x+y=11$

Thus the required linear equation is x + y = 11.