|
|
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
12 May 2020, 03:21
Kudos
Bookmarks
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
15%
(low)
Question Stats:
75% (00:39) correct
25%
(00:45)
wrong
based on 106
sessions
History
Date
Time
Result
Not Attempted Yet
What is the total number of unique prime factors of 450?
A. 2
B. 3
C. 4
D. 5
E. 18
A. 2
B. 3
C. 4
D. 5
E. 18
Updated on: 12 May 2020, 06:31
Originally posted by GMATinsight on 12 May 2020, 03:38.
Last edited by GMATinsight on 12 May 2020, 06:31, edited 1 time in total.
Last edited by GMATinsight on 12 May 2020, 06:31, edited 1 time in total.
Kudos
Bookmarks
Bunuel
\(450 = 5*9*10 = 2*3^2*5^2\)
CONCEPT: Number of factors of \(N = a^p*b^q*c^r...\) are given by \((p+1)*(q+1)*(r+1)*...\)
SO number of factors of 450 = (1+1)*(2+1)*(2+1) = 18
But unique prime factors = {2, 3, 5} only 3
Answer: Option B
12 May 2020, 06:03
Kudos
Bookmarks
Bunuel
Solution
- • \(450 = 45 * 10 = 5*9*2*5 = 2*3^2*5^2\)
• Thus, number of unique prime factors of \(450 = 3\) (i.e. 2, 3, and 5)
