Identifying the Odd Man Out
To determine the odd man out from the series of numbers: 7, 4, 5, 9, 20, 51, and 160.5, we must analyze the characteristics of each number.
Number Analysis
- 7: A prime number
- 4: A composite number (2 x 2)
- 5: A prime number
- 9: A composite number (3 x 3)
- 20: A composite number (4 x 5)
- 51: A composite number (3 x 17)
- 160.5: A decimal number
Key Observations
- Prime Numbers: 7 and 5 are prime.
- Composite Numbers: 4, 9, 20, and 51 are composite.
- Decimal: 160.5 is the only decimal number.
Conclusion
Upon examining these points, 160.5 stands out as the odd man out. Here’s why:
- It is the only number in the list that is not a whole number, deviating from the rest, which are all integers.
- While most numbers can be classified as either prime or composite, 160.5 does not fit into these categories.
Final Answer
Thus, the odd man out in the given series is 160.5 due to its unique status as a decimal, differing from the other whole numbers.