Indices, SM-Bank 047 MC Which of the following numbers is not divisible by 3? 3102 239 42 8121 Show Answers Only \(B\) Show Worked Solution \(\text{A number is divisible by }3\ \text{if the sum of its digits is divisible by }3.\) \(\text{Option A:}\rightarrow\) \(3+1+0+2=6\ \ \checkmark\) \(\text{Option B:}\rightarrow\) \(2+3+9=14\ \ \text{not divisible by 3}\) \(\text{Option C:}\rightarrow\) \(4+2=6\ \ \checkmark\) \(\text{Option D:}\rightarrow\) \(8+1+2+1=12\ \ \checkmark\) \(\Rightarrow B\)