Question

A number consists of two digit number whose sum is 12. if 18 is added to the number , its digit gets deserved. the number is

Answer 1

Answer:

The required number is 57.

Step-by-step explanation:

Let one digit of the number be x , then its ten  digits digits will be (12−x) .  

So , given number =10(12−x)+x  

                                =120−10x+x  

                             =120−9x

Now if digits are reversed  , then Number obtained  

                                =10x+(12−x)

                                =10x+12−x

                                =9x+12

According to question  

       (120−9x)+18=9x+12

        126−9x=9x  

        126=18x

          x=7

⇒ given number  =120−9x

                              =120−9×7      

                              =120−63

                              =57          

                                       

∴ the number is 57.

Answer 2

Answer:

The number is 13

Step-by-step explanation:

Let the digits be X and Y

no. = 10x+y

x+y=4 _______Equation 1

(10x+y) + 18 = 10y +x (given)

9x-9y = -18

x-y = -2 (taking 9 common on both sides)______Equation 2

Adding both equations we get  2x=2

⇒x=1

x+y = 4

1 + y = 4

⇒y=3

Since the no. is 10x+y....10(1)+3 = 13