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. Express the given statement as a linear equation in two variables.

Answer 1

let two digit number be 10x + y and it's reversed two digit number be 10y + x

the sum of a two digit number and the number obtained by reversing the order of it's digits is 121

so, 10x + y + 10y + x = 121
11x + 11y = 121
11(x+y) = 121
x+y = 121/11
x+y = 11

Answer 2

Solution :

Let ten's place digit = y

Unit place digit = x

The number = 10y+x---( 1 )

The number obtained by

reversing the digits=10x+y ---( 2 )

According to the problem

given ,

Sum of ( 1 ) & ( 2 ) = 121

10y + x + 10x + y = 121

=> 11y + 11x = 121

Divide each term with 11 ,

We get

y + x = 11

Therefore ,

Required linear equation in

two variables x and y is

x + y = 11

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