Select the number which is different from the other numbers given below:
`157, 571, 599, 387 `

Options

A. 571
B. 157
C. 599
D. 387

Answer

To solve the problem of identifying the number that is different from the others in the set {157, 571, 599, 387}, we will analyze each number to determine whether they are prime or composite.

### Step-by-Step Solution:

1. **Identify the Numbers**: We have the numbers 157, 571, 599, and 387.

2. **Check if Each Number is Prime or Composite**:
- **157**:
- Check divisibility by prime numbers up to √157 (which is approximately 12.5).
- It is not divisible by 2, 3, 5, 7, or 11.
- Therefore, **157 is a prime number**.

- **571**:
- Check divisibility by prime numbers up to √571 (which is approximately 23.9).
- It is not divisible by 2, 3, 5, 7, 11, 13, 17, 19, or 23.
- Therefore, **571 is a prime number**.

- **599**:
- Check divisibility by prime numbers up to √599 (which is approximately 24.5).
- It is not divisible by 2, 3, 5, 7, 11, 13, 17, 19, or 23.
- Therefore, **599 is a prime number**.

- **387**:
- Check divisibility by prime numbers up to √387 (which is approximately 19.7).
- It is divisible by 3 (387 ÷ 3 = 129).
- Therefore, **387 is a composite number**.

3. **Conclusion**:
- The numbers 157, 571, and 599 are all prime numbers.
- The number 387 is a composite number.
- Thus, **387 is the number that is different from the others**.

### Final Answer:
The number which is different from the others is **387**.