Question

If the digit in the unit and the ten's places of a two digit number
are interchanged, a new number is formed, which is greater than
the original number by 63. Suppose the digit in the unit place of
the original number the x. Then all the possible values of x are :
​

Answer 1

Answer:

8 and 9

Step-by-step explanation:

99-63=33 so the first 33 numbers are the only ones that could possibly have the number made by swapping their digits be 63 greater.

Next we can eliminate 33,32,31,30,22,21,20,11,10,9,8,7,6,5,4,3,2,1 as they are either one digit or have the unit digit less than or equal to their tens digit so swapping them will result in a number smaller than the original number.

We have 12,13,14,15,16,17,18,19,23,24,25,26,27,28,29 left so we can just brute force and we find that the numbers that it works for are 18 and 29.

Therefore x can be 8 or 9