Question

Let abc be a three-digit number. Then abc – cba is not divisible by ______.

विकल्प

• 9

• 11

• 18

• 33

Answer 1

Let abc be a three-digit number. Then abc – cba is not divisible by 18.

Explanation:

Given, abc is a three-digit number.

Then, abc = 100a + 10b + c

And cba = 100c + 10b + a

abc – cba = (100a + 10b + c) – (100c + 10b + a)

= 100a – a + 10b – 10b + c – 100

= 99a – 99c

= 99(a – c)

= abc – cba is divisible by 99.

⇒ abc – cba is divisible by 9, 11, 33, but it is not divisible by 18.