GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 12 Dec 2019, 06:20 ### 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

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.  # The second term of a GP is 1000 and the common ratio is r = 1/n, where

Author Message
TAGS:

### Hide Tags

General GMAT Forum Moderator V
Joined: 15 Jan 2018
Posts: 675
Concentration: General Management, Finance
GMAT 1: 720 Q50 V37 The second term of a GP is 1000 and the common ratio is r = 1/n, where  [#permalink]

### Show Tags

1 00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

### HideShow timer Statistics

The second term of a GP is 1000 and the common ratio is r = 1/n, where n is a natural number. P(n) is the product of n terms of this GP series. If P(6)>P(5) and P(6)>P(7), what is the sum of all possible values of n?

A. 4
B. 5
C. 9
D. 13
E. 15
Manager  G
Joined: 29 Dec 2018
Posts: 60
Location: India
Schools: HBS '22, Wharton '22
Re: The second term of a GP is 1000 and the common ratio is r = 1/n, where  [#permalink]

### Show Tags

If the second term is 1000, then the first term is 1000n
T6 = 1000n/n^5 = 1000/n^4
T7 = 1000n/n^6 = 1000/n^5

Now, P(6) > P(5)
So, T1*T2*T3*T4*T5*T6 > T1*T2*T3*T4*T5
T6>1
1000/n^4 > 1
So, n^4 < 1000

Similarly, P(6)>P(7)
So, T1*T2*T3*T4*T5*T6 > T1*T2*T3*T4*T5*T6*T7
Hence,
T7 < 1
1000/n^5 < 1
n^5> 1000

Finally,
n^4 < 1000 < n^5

Only, 4 and 5 satisfy this range

Hence, sum of values of N is 9

Option C

Posted from my mobile device Re: The second term of a GP is 1000 and the common ratio is r = 1/n, where   [#permalink] 11 Nov 2019, 23:59
Display posts from previous: Sort by

# The second term of a GP is 1000 and the common ratio is r = 1/n, where  