Question

A number consists of two digits whose sum is 5. when the digits are reversed the number becomes greater by 9 find the number. Please give answer with using only 1 variable

Answer 1

Answer:

Here is the answer for your question

Step-by-step explanation:

HI !

Let the number be 10x +y  ,

   x = ten's place  , y = one's place

x + y = 5          ---> [1]

reversed no: ,

10y + x

10x+ y + 9 = 10y+x

9x - 9y = -9

x - y = -1            ---> [2]

Adding equations 1 and 2

x + y = 5

x - y = -1

======

2x = 4

x = 2

x -y = -1

2 - y = -1

2 + 1 = y

3 = y

the number is :-

10x + y 

10 x 2 + 3

 = 23

The no: is 23

Answer 2

Let the ten's digit and the one's digit be x and y respectively.

Given

A number consists of two digits whose sum is 5.

$\implies x+y=5--(1)$

When the digits are reversed the number becomes greater by 9.

$\implies 10y+x=10x+y+9\\\implies -10x+x+10y-y=9\\\implies -9x+9y=9\\\implies -x+y=1--(2)$

Solving (1) and (2), we get,

$x+y=5\\\underline{-x+y=1}\\\underline{\underline{2y=6}}\\\implies y =3$

$\implies x = 2$

Note :-

Such questions can only be solved using 2 variables.

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