Question

Find the greatest number that exactly divides 12, 24 and 40.

• A. 3
• B. 40
• C. 4
• D. 2

Answer 1

Answer:

C. 4

We need the greatest number that divides 12, 24, and 40 → this is the HCF (GCD).

Prime factorization

• $12 = (2^2 \times 3)$

• $24 = (2^3 \times 3)$

• $40 = (2^3 \times 5)$

  Common factors

Common prime = (2)
Lowest power = $(2^2)$

HCF

• $2^2 = 4$
  Final Answer:

4