Find the odd one out:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 93
Option (1) 23 — a prime number: its only factors are 1 and 23.
Option (2) 43 — a prime number: its only factors are 1 and 43.
Option (3) 73 — a prime number: its only factors are 1 and 73.
Option (4) 93 — \(93=3\times31\), so 93 is the odd one out, the only number that is not prime.