Q. 1 D5.0( 3 Votes )

If is a 3-digit number, then



is always divisible by
A. 12

B. 15

C. 18

D. 21

Answer :

Let us collect numbers and their reversal.


Take for instance, , then its reversal is .


We know, in its general form can be written as,



And in its general form can be written as,



Taking their difference, we get






…(i)


Now, take . Expanding each in general form, we get






Then, we get








…(ii)


Adding equations (i) and (ii), we get






n = 18 (a – c)


We can easily say that, n is divisible by 18.

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