Choose the odd one
9105, 9837, 7125, 4314, 3927, 2958
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 9837
A number is divisible by 3 when the sum of its digits is divisible by 3, and by 9 when that sum is divisible by 9. All six numbers have digit sums divisible by 3; only one has a digit sum divisible by 9.
9105: \(9+1+0+5=15\), divisible by 3, not by 9
9837: \(9+8+3+7=27\), divisible by 9, so 9837 is the odd one out
7125: \(7+1+2+5=15\), divisible by 3, not by 9
4314: \(4+3+1+4=12\), divisible by 3, not by 9
3927: \(3+9+2+7=21\), divisible by 3, not by 9
2958: \(2+9+5+8=24\), divisible by 3, not by 9
Tip: When a list of large numbers has no visible pattern, add the digits of each: digit sums show divisibility by 3 and 9 at a glance.