Question

The number 19 + 91 is divisble by:

Answer 1

We know that the number obtained by adding two numbers of the form "ab + ba" is always divisibe by 11.

ab + ba = (10 × a + b) + (10 × b + a)
= (10 + 1) × a + (10 + 1) × b
= 11a + 11b
= 11(a + b)

⇒ This number is always divisible by 11.

So, option d is correct.