It is currently 17 Nov 2017, 13:24
My Tests

Close

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

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

If n ={2^{-10}+2^{-9}}/{(7^{-1}) (5^9)} then n is a terminat

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Manager
Manager
Joined: 20 May 2014
Posts: 234
Followers: 7

Kudos [?]: 30 [0], given: 163

If n ={2^{-10}+2^{-9}}/{(7^{-1}) (5^9)} then n is a terminat [#permalink] New post 12 Nov 2017, 00:05
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
If n =\frac{2^{-10}+2^{-9}}{(7^{-1})(5^9)} then n is a terminating decimal with how many zeroes after the decimal point before the first non-zero digit?

(A) 2

(B) 3

(C) 5

(D) 7

(E) 9


Kudos for correct solution.
[Reveal] Spoiler: OA
Director
Director
Joined: 03 Sep 2017
Posts: 522
Followers: 0

Kudos [?]: 195 [0], given: 66

Re: If n ={2^{-10}+2^{-9}}/{(7^{-1}) (5^9)} then n is a terminat [#permalink] New post 12 Nov 2017, 23:32
In questions about the number of zeroes, we have to look for how many times does 10 appear in our expression. Thus, if we rearrange we get \frac{2^{-9}(2^{-1}+1)}{7^{-1}5^9} = \frac{7(2^{-1}+1)}{2^95^9} = = \frac{10.5)}{10^9}.

Now, we have to check how many zeroes are there after the decimal point but before the first non-zero digit. If we rewrite our expression as 10.5*10^{-9} = 0.105*10^{-7} we get that from the situation in which the first digit after the decimal point is a non-zero digit, we have to move the point back 7 digits, so that there will be 7 zero digits before the 1.

Answer D
Re: If n ={2^{-10}+2^{-9}}/{(7^{-1}) (5^9)} then n is a terminat   [#permalink] 12 Nov 2017, 23:32
Display posts from previous: Sort by

If n ={2^{-10}+2^{-9}}/{(7^{-1}) (5^9)} then n is a terminat

  Question banks Downloads My Bookmarks Reviews Important topics  


GRE Prep Club Forum Home| About| Terms of Use| GRE Prep Club Rules| Contact

Powered by phpBB © phpBB Group

Kindly note that the GRE® test is a registered trademark of the Educational Testing Service®, and this site has neither been reviewed nor endorsed by ETS®.