Oct 14 08:00 PM PDT  11:00 PM PDT Join a 4day FREE online boot camp to kick off your GMAT preparation and get you into your dream bschool in R2.**Limited for the first 99 registrants. Register today! Oct 15 12:00 PM PDT  01:00 PM PDT Join this live GMAT class with GMAT Ninja to learn to conquer your fears of long, kooky GMAT questions. Oct 16 08:00 PM PDT  09:00 PM PDT EMPOWERgmat is giving away the complete Official GMAT Exam Pack collection worth $100 with the 3 Month Pack ($299) Oct 19 07:00 AM PDT  09:00 AM PDT Does GMAT RC seem like an uphill battle? eGMAT is conducting a free webinar to help you learn reading strategies that can enable you to solve 700+ level RC questions with at least 90% accuracy in less than 10 days. Sat., Oct 19th at 7 am PDT Oct 20 07:00 AM PDT  09:00 AM PDT Get personalized insights on how to achieve your Target Quant Score.
Author 
Message 
TAGS:

Hide Tags

Retired Moderator
Joined: 29 Oct 2013
Posts: 252
Concentration: Finance
GPA: 3.7
WE: Corporate Finance (Retail Banking)

In a sequence k, each term after the second term is the sum
[#permalink]
Show Tags
11 Aug 2014, 03:29
Question Stats:
84% (01:21) correct 16% (01:24) wrong based on 344 sessions
HideShow timer Statistics
In a sequence k, each term after the second term is the sum of the two previous terms. What is the first term of sequence K? (1) one term of sequence K is 29 (2) The 4th and 5th terms of K are 11 and 18, respectively
Official Answer and Stats are available only to registered users. Register/ Login.
_________________
Please contact me for super inexpensive quality private tutoring
My journey V46 and 750 > http://gmatclub.com/forum/myjourneyto46onverbal750overall171722.html#p1367876




Magoosh GMAT Instructor
Joined: 28 Dec 2011
Posts: 4473

Re: In a sequence k, each term after the second term is the sum
[#permalink]
Show Tags
11 Aug 2014, 16:48
MensaNumber wrote: In a sequence k, each term after the second term is the sum of the two previous terms. What is the first term of sequence K?
1)one term of sequence K is 29 2)The 4th and 5th terms of K are 11 and 18, respectively Dear MensaNumber, I'm happy to help. Incidentally, a sequence following this pattern is known as a Fibonacci sequence. The most famous one, {1, 1, 2, 3, 5, etc.} has deep connections to the Golden Ratio and to many structures in Nature. See: http://www.goldennumber.net/category/math/In this problem is another Fibonacci sequence. Statement #1: if we know one term is 29, then it may be that this is the third term, after 14 and 15, or 1 and 28, or 2 and 31, or etc. Or, it may be a later term, the fourth or fifth or sixth, in which case the first term could be almost anything. On the basis of this piece of information, we know nothing. Statement #2: a4 = 11 and a5 = 18. We know a3 + a4 = a5, so a3 + 11 = 18, and a3 = 7 Then, we know a2 + a3 = a4, so a2 + 7 = 11, and a2 = 4 Then, we know a1 + a2 = a3, so a1 + 4 = 7, so a1 = 3 This statement, alone and by itself, is sufficient for answering the prompt question. Answer = (B)Does all this make sense? Mike
_________________
Mike McGarry Magoosh Test PrepEducation is not the filling of a pail, but the lighting of a fire. — William Butler Yeats (1865 – 1939)




Manager
Joined: 22 Feb 2009
Posts: 157

Re: In a sequence k, each term after the second term is the sum
[#permalink]
Show Tags
11 Aug 2014, 21:48
MensaNumber wrote: In a sequence k, each term after the second term is the sum of the two previous terms. What is the first term of sequence K?
1)one term of sequence K is 29 2)The 4th and 5th terms of K are 11 and 18, respectively Sequene k: a; b; a + b; a+2b; 2a + 3b (1) one term of sequence K is 29, For example: 2a+3b = 29, there is many solution for a and b > insufficient (2) a + 2b = 11 and 2a + 3b = 18 > a = 7 > sufficient
_________________
......................................................................... +1 Kudos please, if you like my post



Intern
Joined: 17 Jan 2016
Posts: 19

In a sequence k, each term after the second term is the sum
[#permalink]
Show Tags
12 Sep 2016, 21:05
Are we supposed to ignore negative numbers when dealing with sequence problems? For example, I wrote out the numbers of statement 2 and found it to be insufficient ~ 3, 1, 2, 1, 3, 4, 7, 11, 18 (going backwards to negative infiniti) Am i overthinking it?



Intern
Joined: 17 Jan 2016
Posts: 19

Re: In a sequence k, each term after the second term is the sum
[#permalink]
Show Tags
17 Sep 2016, 15:53
I think this is a poor quality question and the explanation is not clear enough.



Board of Directors
Status: Stepping into my 10 years long dream
Joined: 18 Jul 2015
Posts: 3584

In a sequence k, each term after the second term is the sum
[#permalink]
Show Tags
17 Sep 2016, 23:33
wmichaelxie wrote: Are we supposed to ignore negative numbers when dealing with sequence problems? For example, I wrote out the numbers of statement 2 and found it to be insufficient ~ 3, 1, 2, 1, 3, 4, 7, 11, 18 (going backwards to negative infiniti) Am i overthinking it? wmichaelxie wrote: I think this is a poor quality question and the explanation is not clear enough. I must say you are overthinking this. This is an easy question and much clear on everything. We are given that 4th term is 11 and 5th term is 18. So, in the sequence you have mentioned above, I couldn't see your statement 2 is matching. So, its an incorrect sequence. If I take a sequence as a, b, a + b, a + 2b, 2a + 3b ,.. so on. I will get a + 2b = 11 and 2a + 3b = 18. On solving these equations, we will get a = 3. Hence, B is sufficient.
_________________
My LinkedIn abhimahna.My GMAT Story: From V21 to V40My MBA Journey: My 10 years long MBA DreamMy Secret Hacks: Best way to use GMATClub  Importance of an Error Log!Verbal Resources: All SC Resources at one place  All CR Resources at one placeBlog: Subscribe to Question of the Day BlogGMAT Club Inbuilt Error Log Functionality  View More. New Visa Forum  Ask all your Visa Related Questions  here. New! Best Reply Functionality on GMAT Club!Find a bug in the new email templates and get rewarded with 2 weeks of GMATClub Tests for freeCheck our new About Us Page here.



Magoosh GMAT Instructor
Joined: 28 Dec 2011
Posts: 4473

Re: In a sequence k, each term after the second term is the sum
[#permalink]
Show Tags
18 Sep 2016, 13:23
abhimahna wrote: wmichaelxie wrote: Are we supposed to ignore negative numbers when dealing with sequence problems? For example, I wrote out the numbers of statement 2 and found it to be insufficient ~ 3, 1, 2, 1, 3, 4, 7, 11, 18 (going backwards to negative infiniti) Am i overthinking it? wmichaelxie wrote: I think this is a poor quality question and the explanation is not clear enough. I must say you are overthinking this. This is an easy question and much clear on everything. We are given that 4th term is 11 and 5th term is 18. So, in the sequence you have mentioned above, I couldn't see your statement 2 is matching. So, its an incorrect sequence. If I take a sequence as a, b, a + b, a + 2b, a + 3b ,.. so on. I will get a + 2b = 11 and a + 3b = 18. On solving these equations, we will get a = 3. Hence, B is sufficient. Dear abhimahna, My friend, you found the correct answer, but the algebraic representations you used ( a, b, a + b, a + 2b, a + 3b, ...) are not correct for a recursive series. The fifth term would be 2a + 3b. Perhaps you knew this already, because you found the correct answer. Mike
_________________
Mike McGarry Magoosh Test PrepEducation is not the filling of a pail, but the lighting of a fire. — William Butler Yeats (1865 – 1939)



Board of Directors
Status: Stepping into my 10 years long dream
Joined: 18 Jul 2015
Posts: 3584

In a sequence k, each term after the second term is the sum
[#permalink]
Show Tags
21 Sep 2016, 05:44
mikemcgarry wrote: abhimahna wrote: wmichaelxie wrote: Are we supposed to ignore negative numbers when dealing with sequence problems? For example, I wrote out the numbers of statement 2 and found it to be insufficient ~ 3, 1, 2, 1, 3, 4, 7, 11, 18 (going backwards to negative infiniti) Am i overthinking it? wmichaelxie wrote: I think this is a poor quality question and the explanation is not clear enough. I must say you are overthinking this. This is an easy question and much clear on everything. We are given that 4th term is 11 and 5th term is 18. So, in the sequence you have mentioned above, I couldn't see your statement 2 is matching. So, its an incorrect sequence. If I take a sequence as a, b, a + b, a + 2b, a + 3b ,.. so on. I will get a + 2b = 11 and a + 3b = 18. On solving these equations, we will get a = 3. Hence, B is sufficient. Dear abhimahna, My friend, you found the correct answer, but the algebraic representations you used ( a, b, a + b, a + 2b, a + 3b, ...) are not correct for a recursive series. The fifth term would be 2a + 3b. Perhaps you knew this already, because you found the correct answer. Mike Hey Mike ( @mikemcgarry), thanks for pointing that out. It was actually a typo error. I used the 5th term as 2a + 3b only to get to the answer. Original answer corrected. Thanks
_________________
My LinkedIn abhimahna.My GMAT Story: From V21 to V40My MBA Journey: My 10 years long MBA DreamMy Secret Hacks: Best way to use GMATClub  Importance of an Error Log!Verbal Resources: All SC Resources at one place  All CR Resources at one placeBlog: Subscribe to Question of the Day BlogGMAT Club Inbuilt Error Log Functionality  View More. New Visa Forum  Ask all your Visa Related Questions  here. New! Best Reply Functionality on GMAT Club!Find a bug in the new email templates and get rewarded with 2 weeks of GMATClub Tests for freeCheck our new About Us Page here.



Intern
Joined: 17 Jan 2016
Posts: 19

Re: In a sequence k, each term after the second term is the sum
[#permalink]
Show Tags
22 Sep 2016, 20:37
Great, thank you. I missed that.



Director
Status: Come! Fall in Love with Learning!
Joined: 05 Jan 2017
Posts: 535
Location: India

In a sequence k, each term after the second term is the sum
[#permalink]
Show Tags
23 Feb 2017, 06:10
Prompt analysis An = An1 +An2 Superset The answer will be a real number Translation In order to find the answer, we need: 1# exact value of 1st term 2# any other information to find the 1st term thruogh the equation Statement analysis St 1: we know the one term. But we don't know the break of that term as in what two numbers have formed 29. INSUFFICIENT St 2: 5th term =4th term +3rd term. Therfore 3rd term = 7. Similarly 4th term = 3rd term +2nd term. Therfore 2nd term = 4 and similarly 1st term is 3. ANSWER Option B
_________________
GMAT Mentors



NonHuman User
Joined: 09 Sep 2013
Posts: 13112

Re: In a sequence k, each term after the second term is the sum
[#permalink]
Show Tags
20 Mar 2018, 10:52
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.
_________________




Re: In a sequence k, each term after the second term is the sum
[#permalink]
20 Mar 2018, 10:52






