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

It is currently 23 Sep 2018, 13:09

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

M24-18

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

Hide Tags

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 49320
M24-18  [#permalink]

Show Tags

New post 16 Sep 2014, 01:21
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

89% (00:30) correct 11% (00:17) wrong based on 114 sessions

HideShow timer Statistics

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 49320
Re M24-18  [#permalink]

Show Tags

New post 16 Sep 2014, 01:21
Intern
Intern
avatar
Joined: 21 Jan 2015
Posts: 21
GMAT ToolKit User Premium Member
Re: M24-18  [#permalink]

Show Tags

New post 23 Aug 2015, 08:54
I think this is a poor-quality question and I agree with explanation. I was confused by the stem. Is it possible to make it more obvious that we are supposed to find consecutive integers from 1 to 49 and not some fancy exponents ?
sorry, I might be tired from GMAT :)
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 49320
Re: M24-18  [#permalink]

Show Tags

New post 23 Aug 2015, 10:32
Barnal wrote:
I think this is a poor-quality question and I agree with explanation. I was confused by the stem. Is it possible to make it more obvious that we are supposed to find consecutive integers from 1 to 49 and not some fancy exponents ?
sorry, I might be tired from GMAT :)


Edited as suggested. Hope it's better now.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Manager
Manager
User avatar
G
Joined: 15 Nov 2016
Posts: 144
Concentration: General Management, Leadership
Re: M24-18  [#permalink]

Show Tags

New post 10 Oct 2017, 05:26
What is 1+2+3+...+..+48+49 ?

A. 1168
B. 1176
C. 1195
D. 1215
E. 1225

An alternate approach:

Average = sum of integers x No. of integers

Average = Last term + First term / 2

Average = 25
No of terms = 49

25x49=1225

E is the answer.
Intern
Intern
avatar
B
Joined: 02 Feb 2016
Posts: 27
Location: United States
GMAT 1: 710 Q49 V38
GPA: 3.5
Premium Member Reviews Badge
Re: M24-18  [#permalink]

Show Tags

New post 10 Oct 2017, 06:00
Sum of consecutive integers (starting at 1): n(n+1)/2

49(49+1)/2 = 49*50/2 = 1225


Sent from my iPhone using GMAT Club Forum
Manager
Manager
avatar
S
Joined: 17 Jul 2017
Posts: 116
Location: India
GMAT 1: 690 Q50 V33
GMAT 2: 750 Q50 V40
WE: Engineering (Transportation)
Re: M24-18  [#permalink]

Show Tags

New post 06 Feb 2018, 10:31
1
Hi,

1,2,3..49 is an AP series.

So for that we can take the sum as averageXno of integers

Here average = (first term+last term)/2--> 1+49/2=25

Sum =25x49 = 1225
Intern
Intern
avatar
B
Joined: 06 Jan 2018
Posts: 16
Schools: INSEAD Jan '19
GMAT 1: 790 Q50 V51
Re: M24-18  [#permalink]

Show Tags

New post 03 Mar 2018, 02:00
Agree with previous calculations.

You also don't really need to count how many multiples of 50 there are (e.g. (1+49) + (2+48) etc).

You can realise very quickly that 25 will be "on its own" (as 25+25 would equal 50 but obviously we can't have 2 copies of the same number).

Therefore the final answer will either end with 25 (if there are an even number of multiples of 50) or 75 (if there are an odd number of multiples of 50).

Only 1225 satisfies this requirement so you can almost do this one "at a glance".
Director
Director
User avatar
S
Joined: 08 Jun 2015
Posts: 503
Location: India
GMAT 1: 640 Q48 V29
GMAT 2: 700 Q48 V38
GPA: 3.33
Premium Member CAT Tests
Re: M24-18  [#permalink]

Show Tags

New post 01 May 2018, 05:41
+1 for option E. Use sum of consecutive numbers formula. The answer comes to 1225. Option E it is !!
_________________

" The few , the fearless "

Intern
Intern
avatar
B
Joined: 22 Jan 2018
Posts: 19
Re: M24-18  [#permalink]

Show Tags

New post 20 Jun 2018, 07:53
This is an arithmetic sequence. Sum = n x 2 first term + (n-1)d / 2 !
GMAT Club Bot
Re: M24-18 &nbs [#permalink] 20 Jun 2018, 07:53
Display posts from previous: Sort by

M24-18

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

Moderators: chetan2u, Bunuel

Events & Promotions

PREV
NEXT


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| 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®.