Which number is divisible by both 3 and 9? A. 21,369 B. 27,621 C. 27,629 D. 36,663

To determine which number is divisible by both 3 and 9, we need to check each option one by one.

A. 21,369 B. 27,621 C. 27,629 D. 36,663

Step 1: Check if the number is divisible by 3. A number is divisible by 3 if the sum of its digits is divisible by 3.

Step 2: Check if the number is divisible by 9. A number is divisible by 9 if the sum of its digits is divisible by 9.

Let's start:

A. 21,369: The sum of the digits is 2+1+3+6+9 = 21, which is divisible by 3 but not by 9. So, 21,369 is not divisible by both 3 and 9.

B. 27,621: The sum of the digits is 2+7+6+2+1 = 18, which is divisible by both 3 and 9. So, 27,621 is divisible by both 3 and 9.

C. 27,629: The sum of the digits is 2+7+6+2+9 = 26, which is not divisible by 3 or 9. So, 27,629 is not divisible by both 3 and 9.

D. 36,663: The sum of the digits is 3+6+6+6+3 = 24, which is divisible by 3 but not by 9. So, 36,663 is not divisible by both 3 and 9.

So, the answer is B. 27,621.