Question
Find the greatest common factor of 20,65, 80
a
25
b
10
c
5
a
25
b
10
c
5
Answers
GPT-4o mini
To find the greatest common factor (GCF) of the numbers 20, 65, and 80, we can follow these steps:
1. **Find the prime factorization of each number:**
- 20 = 2 × 2 × 5 = \(2^2 \times 5^1\)
- 65 = 5 × 13 = \(5^1 \times 13^1\)
- 80 = 2 × 2 × 2 × 5 = \(2^4 \times 5^1\)
2. **Identify the common factors:**
- The only common prime factor among the three numbers is 5.
3. **Determine the lowest power of the common factors:**
- The lowest power of 5 is \(5^1\).
Thus, the GCF of 20, 65, and 80 is 5.
Therefore, the answer is **c) 5**.
1. **Find the prime factorization of each number:**
- 20 = 2 × 2 × 5 = \(2^2 \times 5^1\)
- 65 = 5 × 13 = \(5^1 \times 13^1\)
- 80 = 2 × 2 × 2 × 5 = \(2^4 \times 5^1\)
2. **Identify the common factors:**
- The only common prime factor among the three numbers is 5.
3. **Determine the lowest power of the common factors:**
- The lowest power of 5 is \(5^1\).
Thus, the GCF of 20, 65, and 80 is 5.
Therefore, the answer is **c) 5**.