Which of the following are the prime factors of 143.

• A. 2 × 11 × 13
• B. 11 × 13
• C. 2 × 3 × 7
• D. None of these

To determine the prime factors of 143, we need to find the prime numbers that multiply together to give 143. Let's break it down:

Identifying Prime Factors

First, we can check if 143 is divisible by smaller prime numbers:

• 143 is odd, so it is not divisible by 2.
• Next, we check 3: the sum of the digits (1 + 4 + 3 = 8) is not divisible by 3.
• For 5, 143 does not end in 0 or 5, so it is not divisible by 5.
• Now, checking 7: 143 ÷ 7 is not a whole number.
• Finally, we try 11: 143 ÷ 11 = 13, which is a whole number.

Conclusion on Prime Factors

Since 143 can be expressed as 11 × 13, the correct answer is:

B. 11 × 13