It is currently 19 Oct 2017, 22:24

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.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Arithmetic Progression

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

1 KUDOS received
BSchool Forum Moderator
User avatar
P
Joined: 12 Aug 2015
Posts: 2212

Kudos [?]: 837 [1], given: 595

GMAT ToolKit User Premium Member CAT Tests
Arithmetic Progression [#permalink]

Show Tags

New post 12 Aug 2016, 07:54
1
This post received
KUDOS
2
This post was
BOOKMARKED
Hi Everyone

I Find that there are several questions on the gmat regarding the Combination of Statistics and Arithmetic Progression.

Just created some bullet Points
If i am missing anything or anyone of these statements is untrue please notify me here




A)AP is a series in which each term after the first term is just a constant being added to its immediate preceding term => a,a+d,a+2d.....,a+(n-1)d

B) a(n)= a+(n-1)d i.e the nth term of any AP e.g=> 23rd term = a+22d

C) s(n) = n/2[2a+(n-1)d]

D)s(n) = n/2[a+l]

E) In an AP Mean = Median = 1/2[sum of last and first term] = 1/2[sum of second and second last term ] and so on.

Here mean = median [as the sum of deviations around the mean is zero]

E.g.
Mean of integers from 45,46,46...100 => (100+45)/2 =72.5
Mean of integers from 200,201,202....300 => (200+300)/2 =250
Additionally
If a,b,c,d,e,f,g, are in AP
Mean = Median = d
Now removing the elements in combination such as a and g or b and f or a,b,f,g doesn't effect the mean or the median
This can easily be understood using the definition of mean => Mean of any dataset is a value for which the sum of deviations around it is zero
After Removing these terms mentioned above the mean does not get effected as still for each and every and every -ve deviation around the mean there is an equal and opposite +ve deviation of same magnitude.

F) Consecutive evens , Consecutive odds , consecutive integers are all AP series


G) Sum of any N consecutive integers is always divisible by N for N being ODD (Not for even)

So the average of N consecutive integers is an integer for N being ODD

H) Product of n consecutive integers is always is always divisible by n!

Anything else ?


Regards
Stone Cold
_________________

Give me a hell yeah ...!!!!!

Kudos [?]: 837 [1], given: 595

1 KUDOS received
NTU Nanyang Thread Master
User avatar
B
Status: It`s Just a pirates life !
Joined: 21 Mar 2014
Posts: 235

Kudos [?]: 16 [1], given: 246

Location: India
Concentration: Strategy, Operations
GMAT 1: 690 Q48 V36
GPA: 4
WE: Consulting (Manufacturing)
Reviews Badge
Arithmetic Progression [#permalink]

Show Tags

New post 24 Aug 2016, 02:07
1
This post received
KUDOS
stonecold wrote:
Hi Everyone

I Find that there are several questions on the gmat regarding the Combination of Statistics and Arithmetic Progression.

Just created some bullet Points
If i am missing anything or anyone of these statements is untrue please notify me here




A)AP is a series in which each term after the first term is just a constant being added to its immediate preceding term => a,a+d,a+2d.....,a+(n-1)d

B) a(n)= a+(n-1)d i.e the nth term of any AP e.g=> 23rd term = a+22d

C) s(n) = n/2[2a+(n-1)d]

D)s(n) = n/2[a+l]

E) In an AP Mean = Median = 1/2[sum of last and first term] = 1/2[sum of second and second last term ] and so on.

Here mean = median [as the sum of deviations around the mean is zero]

E.g.
Mean of integers from 45,46,46...100 => (100+45)/2 =72.5
Mean of integers from 200,201,202....300 => (200+300)/2 =250
Additionally
If a,b,c,d,e,f,g, are in AP
Mean = Median = d
Now removing the elements in combination such as a and g or b and f or a,b,f,g doesn't effect the mean or the median
This can easily be understood using the definition of mean => Mean of any dataset is a value for which the sum of deviations around it is zero
After Removing these terms mentioned above the mean does not get effected as still for each and every and every -ve deviation around the mean there is an equal and opposite +ve deviation of same magnitude.

F) Consecutive evens , Consecutive odds , consecutive integers are all AP series


G) Sum of any N consecutive integers is always divisible by N for N being ODD (Not for even)

So the average of N consecutive integers is an integer for N being ODD

H) Product of n consecutive integers is always is always divisible by n!

Anything else ?


Regards
Stone Cold


Hi Bro, You have made a comprehensive collection:

Just to top a few,

1. Series 2,4,6.........2836

No of elements in this series (N) = ((L - A)/D) + 1

L - last term - 2836
A - First term - 2
D - Common Difference - 2

N = ((2836-2)/2)+1 = 1418 elements

2. Consider three elements : 1,2,3

Arithmetic mean = (1+2+3)/3 = 2

geometric mean = nth root(a*b*....n) = cube root(1*2*3) = cube root(6) = 1.817

Cheers
Balaji
_________________

Aiming for a 3 digit number with 7 as hundredths Digit

Kudos [?]: 16 [1], given: 246

GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 09 Sep 2013
Posts: 16646

Kudos [?]: 273 [0], given: 0

Premium Member
Re: Arithmetic Progression [#permalink]

Show Tags

New post 18 Sep 2017, 06:59
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

Kudos [?]: 273 [0], given: 0

Re: Arithmetic Progression   [#permalink] 18 Sep 2017, 06:59
Display posts from previous: Sort by

Arithmetic Progression

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.