GMAT Quantitative: Number Properties 4

Question 1

If n^2 is even, what can be concluded about n?

Accepted Answer

n is even

Answer

If n were odd then n^2 would be odd, so an even n^2 forces n to be even.

Question 2

How many integers between 1 and 100 inclusive are divisible by 7?

Accepted Answer

14

Answer

The multiples are 7 through 98, and 98/7 = 14, giving 14 integers.

Question 3

What is the units digit of 4^15?

Accepted Answer

4

Answer

Units digits of 4^n alternate 4,6,4,6; odd exponents give 4, so 4^15 ends in 4.

Question 4

Which of the following is divisible by 11?

Accepted Answer

121

Answer

121 = 11 * 11, so it is divisible by 11.

Question 5

If x and y are integers and xy is odd, then:

Accepted Answer

Both x and y are odd

Answer

A product is odd only when every factor is odd, so both x and y must be odd.

GMAT Practice Test