Question

Which of the following numbers are divisible by $9$ ?

• A. $81$
• B. $99$
• C. $108$
• D. All of the above

Answer 1

The correct option is D All of the above

A number is divisible by $9$, if the sum of the digits is also divisible by $9$.

Sum of digits of $81$ is $8+1=9$

Sum of digits of $99$ is $9+9=18$

Sum of digits of $108$ is $1+0+8=9$

Thus, all given numbers are divisible by $9$

So, option D is correct.