Question

the sum of two digits of the two digit no.is 7 .If the number obtained by interchanging the digit is 27 more than the original no. find original no.​

Answer 1

Answer:

Let the unit digit be x , then tens place digit will be 3−x

So, the given number = x+10(3−x)

= x+30−10x

= 30−9x

If digits are interchanged , then the number obtained = 10x+3−x

= 9x+3

According to question

9x+3 = 30−9x−9

⇒18x=18

⇒ x=1

So , 3−x =3−1=2

Hence the required number is 21