Author 
Message 
TAGS:

Hide Tags

Intern
Joined: 04 Mar 2012
Posts: 47

If S is the sum of reciprocals of a list of consecutive [#permalink]
Show Tags
16 May 2012, 09:35
9
This post was BOOKMARKED
Question Stats:
67% (01:54) correct
33% (00:52) wrong based on 339 sessions
HideShow timer Statistics
If S is the sum of reciprocals of a list of consecutive integers from 45 to 54, inclusive, S is approximately equal to A. 0.1 B. 0.2 C. 0.3 D. 0.4 E. 0.5
Official Answer and Stats are available only to registered users. Register/ Login.
Last edited by Bunuel on 13 Aug 2014, 03:12, edited 1 time in total.
Added the OA.



Math Expert
Joined: 02 Sep 2009
Posts: 39598

Re: If S is the sum of reciprocals of a list of consecutive [#permalink]
Show Tags
16 May 2012, 09:42
1
This post received KUDOS
Expert's post
7
This post was BOOKMARKED



Intern
Joined: 24 Feb 2011
Posts: 7

Re: If S is the sum of reciprocals of a list of consecutive [#permalink]
Show Tags
24 Aug 2012, 04:27
Are these kind of progressions tested on the GMAT?



Retired Moderator
Status: 2000 posts! I don't know whether I should feel great or sad about it! LOL
Joined: 04 Oct 2009
Posts: 1662
Location: Peru
Schools: Harvard, Stanford, Wharton, MIT & HKS (Government)
WE 1: Economic research
WE 2: Banking
WE 3: Government: Foreign Trade and SMEs

Re: If S is the sum of reciprocals of a list of consecutive [#permalink]
Show Tags
24 Aug 2012, 10:09
1
This post received KUDOS
+1 B All those numbers are close to 0.02. Amogh: yes, that would be a GMAT question. You don't have to calculate, just estimate.
_________________
"Life’s battle doesn’t always go to stronger or faster men; but sooner or later the man who wins is the one who thinks he can."
My Integrated Reasoning Logbook / Diary: http://gmatclub.com/forum/myirlogbookdiary133264.html
GMAT Club Premium Membership  big benefits and savings



Intern
Joined: 11 Jul 2012
Posts: 46

Re: If S is the sum of reciprocals of a list of consecutive [#permalink]
Show Tags
05 Nov 2012, 15:18
I got 0.2 too (B). Please help. Here is my approach (1/45) + (1/46) + .....+(1/54) = (4544)/45 +(4645)/46 +.....+(5453)/54 = 10 (44/45 + 45/46 + ...53/54). Each term in the bracket is > 0.977, and there are ten of them. Then their sum is roughly 9.8 109.8 = 0.2. But is this doable in 2 mn under stress and heat? Brother Karamazov
Brother Karamazov



Intern
Status: wants to beat the gmat
Joined: 18 Jul 2012
Posts: 20
Location: United States

Re: If S is the sum of reciprocals of a list of consecutive [#permalink]
Show Tags
06 Nov 2012, 13:47
my method was 1/45 + 1/46 + ... => 10/45 ~ 2/9 ~ .2



Senior Manager
Joined: 13 Aug 2012
Posts: 464
Concentration: Marketing, Finance
GPA: 3.23

Re: If S is the sum of reciprocals of a list of consecutive [#permalink]
Show Tags
19 Dec 2012, 03:59
2
This post received KUDOS
5
This post was BOOKMARKED
gmihir wrote: If S is the sum of reciprocals of a list of consecutive integers from 45 to 54, inclusive, S is approximately equal to
A. 0.1 B. 0.2 C. 0.3 D. 0.4 E. 0.5
Sorry, don't have an official answer. Solved this using Bunuel's technique that I saw on another similar problem. S = \(\frac{1}{45}+\frac{1}{46}+...+\frac{1}{54}\) Get number of terms: \(54  45 + 1 = 10\) Get lower limit: \(10*\frac{1}{54}=\frac{5}{27}=0.18\) Get upper limit: \(10*\frac{1}{45}=\frac{2}{9}=0.22\) \(0.18<S<0.22\) Answer: B
_________________
Impossible is nothing to God.



GMAT Club Legend
Joined: 09 Sep 2013
Posts: 15922

Re: If S is the sum of reciprocals of a list of consecutive [#permalink]
Show Tags
12 Aug 2014, 15:28
Hello from the GMAT Club BumpBot! Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up  doing my job. I think you may find it valuable (esp those replies with Kudos). Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
GMAT Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources



SVP
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1857
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)

Re: If S is the sum of reciprocals of a list of consecutive [#permalink]
Show Tags
12 Aug 2014, 21:39
1
This post received KUDOS
gmihir wrote: If S is the sum of reciprocals of a list of consecutive integers from 45 to 54, inclusive, S is approximately equal to
A. 0.1 B. 0.2 C. 0.3 D. 0.4 E. 0.5
Sorry, don't have an official answer. Bunuel, Kindly update OA for this question (Answer = B) Thanks
_________________
Kindly press "+1 Kudos" to appreciate



Math Expert
Joined: 02 Sep 2009
Posts: 39598

Re: If S is the sum of reciprocals of a list of consecutive [#permalink]
Show Tags
13 Aug 2014, 03:14



GMAT Club Legend
Joined: 09 Sep 2013
Posts: 15922

Re: If S is the sum of reciprocals of a list of consecutive [#permalink]
Show Tags
08 Nov 2015, 20:48
Hello from the GMAT Club BumpBot! Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up  doing my job. I think you may find it valuable (esp those replies with Kudos). Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
GMAT Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources



Senior Manager
Joined: 20 Aug 2015
Posts: 396
Location: India

Re: If S is the sum of reciprocals of a list of consecutive [#permalink]
Show Tags
09 Nov 2015, 03:15
gmihir wrote: If S is the sum of reciprocals of a list of consecutive integers from 45 to 54, inclusive, S is approximately equal to
A. 0.1 B. 0.2 C. 0.3 D. 0.4 E. 0.5 Such questions do not test your calculations. (In fact most of GMAT questions) They test your logic and how easily can you simplify a problem. That is why an approximate result is asked and not the absolute value.Out of the given numbers, from 45 to 54, carrying out calculations with 50 would be easiest. Hene instead of 1/45 + 1/46 + ... 1/50 + ... + 1/54, We can increase some terms and decrease some terms by changing the numbers with 50 Hence we have a sequence = 1/50 + 1/50 + ... + 1/50 (Total 20 terms) = 10/50 = 1/5 = 0.2 approximately Option B
_________________
Reach out to us at bondwithus@gmatify.com



GMAT Club Legend
Joined: 09 Sep 2013
Posts: 15922

Re: If S is the sum of reciprocals of a list of consecutive [#permalink]
Show Tags
15 Dec 2016, 04:00
Hello from the GMAT Club BumpBot! Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up  doing my job. I think you may find it valuable (esp those replies with Kudos). Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
GMAT Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources



Intern
Joined: 26 Dec 2016
Posts: 20

Re: If S is the sum of reciprocals of a list of consecutive [#permalink]
Show Tags
13 Feb 2017, 05:20
TeamGMATIFY wrote: gmihir wrote: If S is the sum of reciprocals of a list of consecutive integers from 45 to 54, inclusive, S is approximately equal to
A. 0.1 B. 0.2 C. 0.3 D. 0.4 E. 0.5 Such questions do not test your calculations. (In fact most of GMAT questions) They test your logic and how easily can you simplify a problem. That is why an approximate result is asked and not the absolute value.Out of the given numbers, from 45 to 54, carrying out calculations with 50 would be easiest. Hene instead of 1/45 + 1/46 + ... 1/50 + ... + 1/54, We can increase some terms and decrease some terms by changing the numbers with 50 Hence we have a sequence = 1/50 + 1/50 + ... + 1/50 (Total 20 terms)= 10/50 = 1/5 = 0.2 approximately Option B Hi, aren't there 10 terms and not 20 ? regards



Target Test Prep Representative
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 1044

Re: If S is the sum of reciprocals of a list of consecutive [#permalink]
Show Tags
14 Feb 2017, 16:55
gmihir wrote: If S is the sum of reciprocals of a list of consecutive integers from 45 to 54, inclusive, S is approximately equal to
A. 0.1 B. 0.2 C. 0.3 D. 0.4 E. 0.5 We need to determine the approximate value of the sum of the reciprocals from 45 to 54 inclusive; thus, we need the approximate value of the following: 1/45 + 1/46 + 1/47 + 1/48 + 1/49 + 1/50 + 1/51 + 1/52 + 1/53 + 1/54 Rather than adding each of these numbers (which would be incredibly timeconsuming), let’s strategically select one of the fractions in our list and add it to itself 10 times. That sum will give us an approximate value for S. Scanning the list, we see the best number to add to itself 10 times is 1/50. However, instead of actually adding 1/50 ten times, we will simply multiply it by 10: 1/50 x 10 = 10/50 = 1/5 = 0.2 Thus, we see that S is approximately 0.2. Answer: B
_________________
Jeffery Miller
Head of GMAT Instruction
GMAT Quant SelfStudy Course
500+ lessons 3000+ practice problems 800+ HD solutions




Re: If S is the sum of reciprocals of a list of consecutive
[#permalink]
14 Feb 2017, 16:55







