Events & Promotions
|
|
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.
Apr 2808:00 AM PDT
-11:00 AM PDT
Whether you are just beginning your MBA journey or fine-tuning your path to a 700+ score, GMAT Day is designed to give you a competitive edge.
02 Dec 2016, 14:09
Kudos
Bookmarks
D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
25%
(medium)
Question Stats:
71% (00:42) correct
29%
(01:21)
wrong
based on 353
sessions
History
Date
Time
Result
Not Attempted Yet
How many consecutive zeros will appear at the end of 43! if that number is expanded out to its final result?
A) 12
B) 11
C) 10
D) 9
E) 8
A) 12
B) 11
C) 10
D) 9
E) 8
14 Sep 2018, 17:42
Kudos
Bookmarks
SW4
To determine the number of trailing zeros in a number, we need to determine the number of 5- and-2 pairs within the prime factorization of that number. Each 5-and-2 pair creates a 10, and each 10 creates an additional zero.
Since we know there are fewer 5s in 43! than 2s, we can find the number of 5s and thus be able to determine the number of 5-and-2 pairs.
To determine the number of 5s within 43!, we can use the following shortcut in which we divide 43 by 5, then divide the quotient of 43/5 by 5 and continue this process until we no longer get a nonzero quotient.
43/5 = 8 (we can ignore the remainder)
8/5 = 1 (we can ignore the remainder)
Since 1/5 does not produce a nonzero quotient, we can stop.
The final step is to add up our quotients; that sum represents the number of factors of 5 within 43!.
Thus, there are 8 + 1 = 9 factors of 5 within 43! This means we have nine 5-and-2 pairs, so there are 9 consecutive zeros at the end of 43! when it is expanded to its final result.
Answer: D
General Discussion
02 Dec 2016, 23:14
Kudos
Bookmarks
\(\frac{43}{5} + \frac{43}{5^2} = 8 + 1 = 9\)
Answer D
Answer D
