Question

Find the odd one out:

• A. 23
• B. 43
• C. 73
• D. 93

Hint:

Check for primes: 23, 43, 73 are prime but 93 = 3 x 31.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
We have four numbers and three of them share a property that the fourth does not. We must find the number that does not fit.

Step 2: Key Idea:
Check whether each number is a prime number. A prime has only two factors, 1 and itself.

Step 3: Test each number:
23 has no factor other than 1 and 23, so it is prime. 43 is not divisible by 2, 3, 5 or 7, so it is prime. 73 is not divisible by 2, 3, 5 or 7, so it is prime. 93 has digit sum 9 + 3 = 12, which is divisible by 3, so 93 = 3 x 31 and it is not prime.

Step 4: Check the options:
Options 1, 2 and 3 are primes. Option 4 is composite, so it is the odd one out.

Final Answer:
93 is the odd one out because it is not prime. \[ \boxed{93} \]