AAPL wrote: ↑Wed Oct 14, 2020 12:23 pm
E-GMAT
If n is the product of all odd prime numbers less than 16, how many factors does n have?
A. 5
B. 6
C. 16
D. 32
E. 64
OA
D
Solution:
Recall that to determine the number of positive factors that a number n has, we first prime factorize n and then add 1 to each prime’s exponent. We then calculate the product of those “adjusted” exponents.
First, we prime factorize n:
n = 3^1 x 5^1 x 7^1 x 11^1 x 13^1
We add 1 to each exponent and then find the product of the adjusted exponents. Therefore, n has (1 + 1) x (1 + 1) x (1 + 1) x (1 + 1) x (1 + 1) = 2^5 = 32 factors.
Answer: D
Scott Woodbury-Stewart
Founder and CEO
[email protected]
See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews
