Question

Choose the number that is not divisible by both 3 and 9.

• A.
• B.
• C.
• D.

Answer 1

The correct option is D

A number is divisible by 3 and 9 if the sum of the digits of the number is divisible by 3 and 9 respectively.
Sum of digits of 891003 = 8+9+1+0+0+3 = 21. It is divisible by 3 but not 9.
Sum of digits of 760032 = 7+6+0+0+3+2 = 18. It is divisible by both 3 and 9.
Sum of digits of 348522 = 3+4+8+5+2+2 = 24. It is divisible by 3 but not 9.

Sum of digits of 326555= 3+2+6+5+5+5 = 26. This is neither divisible by 3 nor 9.
Hence 326555 is the correct option.

Here, the sum of the digits is 21 which is divisible by 3 and not by 9.