SAT Math Practice Exam

Answer: A - The Greatest Common Divisor (GCD) is the largest positive integer that divides all the given numbers. Hence the GCD is the biggest size of measuring pot. So find GCD of 12, 15 and 24.
12= 2x2x3
15= 3x5
24= 2x2x2x3

3 is Greatest Common Divisor and so the size of biggest measuring pot to measure all the quantities 12 liters, 15 liters and 24 liters exactly is 3 liters.

Key takeaway: GCF is also known as the Highest Common Factor (HCF) or the Greatest Common Factor (GCF).It is the largest positive integer that divides all the given numbers. Write each number as products of their prime factors. Write out all prime factors that are common to all the numbers. Their product is the GCF.