and . What is the highest common factor of and ?

Answer and explanation

Correct answer: A. 12

  1. Step 1: The HCF uses the lowest power of each prime that appears in both numbers.
  2. Step 2: Powers of : lowest is . Powers of : lowest is . The is only in , so it is left out.
  3. Step 3: .
Answer
12.
Why not the others: 360: This is the lowest common multiple, taking the highest powers of all primes. 72: This takes the highest powers of and but leaves out , which is a partial LCM. 60: This includes the , which is not a factor of .

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