Question

A two digit number is such that the sum of its digit is 4. If 18 are added to yhe number its degits are reversed .find the number

Answer 1

Let the number be 10x + y

According to the given conditions,

x+y=4.........(i)
10x+y+18=10y+x
=9x-9y=-18........(ii)
=x-y=-2......(iii) (dividing ii by 9)

Solving i and iii

x-y= -2
x+y= 4
.........
2x= 2
Therefore, x=1

Now....
x+y=4
= 1 + y = 4
= y = 4-1
= 3

Therefore the required number is 13

Hope it helped.....!

Answer 2

Hey

Here is your answer,

_________________________________________

The number is 10x+y.

The ones place digit is y
And the tens digit is 10x.

According to the question,

X+y=4
------------ equation 1

Given that, 18 is added to the number :

18 + 10 x +y

Then, it's digits are reversed:

10y + x

According to the given statement , the equation obtained is :

18+10x+y=10y+x
10x -x+y-10y=-18
9x-9y=-18

Dividing the equation by 9 and then it becomes ,

X-y=-2
-------------- equation 2

Solving both the equations by elimination method,.

X+y=4
X-y = -2
_______
2x = 2
x=2/2
X=1

Substitute the value of x in equation 1,
X+y=4
Y=4-1
Y=3

The number = 10x+y
=10x 1+3
=10+3
=13

Hope it helps you!