GMAT Quantitative: Number Properties 3

Question 1

What is the greatest common divisor (GCD) of 48 and 60?

Accepted Answer

12

Answer

48 = 2^4*3 and 60 = 2^2*3*5, so the GCD is 2^2*3 = 12.

Question 2

What is the least common multiple (LCM) of 9 and 12?

Accepted Answer

36

Answer

9 = 3^2 and 12 = 2^2*3, so the LCM is 2^2*3^2 = 36.

Question 3

If an integer is divisible by both 4 and 9, it must also be divisible by:

Accepted Answer

36

Answer

Since 4 and 9 are coprime, divisibility by both forces divisibility by 4*9 = 36.

Question 4

Which number is NOT divisible by 3?

Accepted Answer

451

Answer

The digits of 451 sum to 10, which is not divisible by 3.

Question 5

If p and q are both prime numbers greater than 2, then p + q is always:

Accepted Answer

Even

Answer

Primes greater than 2 are odd, and the sum of two odd numbers is even.

GMAT Practice Test