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

It is currently 18 Jun 2019, 00:07

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

Find m if the sum of the consecutive integers from -16 to m, inclusive

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

Hide Tags

 
Intern
Intern
avatar
Joined: 07 Jun 2017
Posts: 6
Find m if the sum of the consecutive integers from -16 to m, inclusive  [#permalink]

Show Tags

New post Updated on: 09 Jun 2017, 05:14
2
10
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

79% (01:50) correct 21% (02:07) wrong based on 161 sessions

HideShow timer Statistics

Find m if the sum of the consecutive integers from -16 to m, inclusive is 74.


A) 17
B) 18
C) 19
D) 20
E) 21

Originally posted by Mina Satti on 09 Jun 2017, 01:02.
Last edited by Bunuel on 09 Jun 2017, 05:14, edited 1 time in total.
Renamed the topic and edited the question.
Manager
Manager
avatar
S
Joined: 30 Mar 2017
Posts: 65
Re: Find m if the sum of the consecutive integers from -16 to m, inclusive  [#permalink]

Show Tags

New post 09 Jun 2017, 01:06
1
1
It will be D 20
As -16 to 16 will cancel out the addition. And then you can simply add 17 ,18 ,19 and 20 to get 74.

Sent from my Moto G (5) Plus using GMAT Club Forum mobile app
CEO
CEO
User avatar
D
Status: GMATINSIGHT Tutor
Joined: 08 Jul 2010
Posts: 2940
Location: India
GMAT: INSIGHT
Schools: Darden '21
WE: Education (Education)
Reviews Badge
Re: Find m if the sum of the consecutive integers from -16 to m, inclusive  [#permalink]

Show Tags

New post 09 Jun 2017, 04:24
1
Mina Satti wrote:
Question. Find m if the sum of the consecutive integers from -16 to m, inclusive is 74.


A) 17, B)18 C) 19 D) 20


Sum of all consecutive integers from -16 to +16 = 0

Now sum of 17+18+19+20=74

Hence m= 20

Answer option D

Bunuel please increase one option here to make it a GMAT like question .

Add an option E)21
_________________
Prosper!!!
GMATinsight
Bhoopendra Singh and Dr.Sushma Jha
e-mail: info@GMATinsight.com I Call us : +91-9999687183 / 9891333772
Online One-on-One Skype based classes and Classroom Coaching in South and West Delhi
http://www.GMATinsight.com/testimonials.html

ACCESS FREE GMAT TESTS HERE:22 ONLINE FREE (FULL LENGTH) GMAT CAT (PRACTICE TESTS) LINK COLLECTION
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 55640
Re: Find m if the sum of the consecutive integers from -16 to m, inclusive  [#permalink]

Show Tags

New post 09 Jun 2017, 05:16
GMATinsight wrote:
Mina Satti wrote:
Question. Find m if the sum of the consecutive integers from -16 to m, inclusive is 74.


A) 17, B)18 C) 19 D) 20


Sum of all consecutive integers from -16 to +16 = 0

Now sum of 17+18+19+20=74

Hence m= 20

Answer option D

Bunuel please increase one option here to make it a GMAT like question .

Add an option E)21


Done. Thank you for the suggestion.
_________________
VP
VP
User avatar
D
Status: Learning
Joined: 20 Dec 2015
Posts: 1007
Location: India
Concentration: Operations, Marketing
GMAT 1: 670 Q48 V36
GRE 1: Q157 V157
GPA: 3.4
WE: Engineering (Manufacturing)
Reviews Badge
Re: Find m if the sum of the consecutive integers from -16 to m, inclusive  [#permalink]

Show Tags

New post 09 Jun 2017, 07:52
Imo D
Can be calculated from sum formula of a sequence

Sent from my ONE E1003 using GMAT Club Forum mobile app
_________________
Please give kudos if you found my answers useful
Manager
Manager
avatar
S
Joined: 05 Nov 2016
Posts: 85
GMAT ToolKit User
Re: Find m if the sum of the consecutive integers from -16 to m, inclusive  [#permalink]

Show Tags

New post 09 Jun 2017, 13:01
Opt D
Other way round
S = n/2(2a+(n-1)d)
=> 74=n/2(-32+n-1) as common difference is 1
148=-33n+n^2
n^2-33n-148=0
upon simplification n = 37
tn=a+(n-1)d
m=16+(37-1)1
m=20
_________________
Kudos are always welcome ... as well your suggestions
Target Test Prep Representative
User avatar
G
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2823
Re: Find m if the sum of the consecutive integers from -16 to m, inclusive  [#permalink]

Show Tags

New post 13 Jun 2017, 12:08
1
Mina Satti wrote:
Find m if the sum of the consecutive integers from -16 to m, inclusive is 74.


A) 17
B) 18
C) 19
D) 20
E) 21


We can use the following formula:

sum = average x quantity

Since we have a set of evenly spaced integers, the average is (-16 + m)/2.

We can also calculate the quantity as m - (-16) + 1 = m + 17.

Thus:

74 = (-16 + m)/2 x (m + 17)

148 = (m - 16)(m + 17)

148 = m^2 + m - 272

m^2 + m - 420 = 0

(m + 21)(m - 20) = 0

m = -21 or m = 20

Since m > -16, m must be 20.

Alternate Solution:

The integers in the sum will be -16, -15, -14, …, -2, -1, 0, +1, +2, …, m. Notice that all the negative integers from -16 to -1 inclusive will be offset by the positive integers from +1 to +16, yielding a net sum of 0. So now, starting with the integer +17, we need to add consecutive integers until we get a sum of 74. We see that 17 + 18 + 19 + 20 = 74, and thus m = 20, the largest integer in the set.

Answer: D
_________________

Jeffrey Miller

Head of GMAT Instruction

Jeff@TargetTestPrep.com
TTP - Target Test Prep Logo
122 Reviews

5-star rated online GMAT quant
self study course

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button.

VP
VP
avatar
P
Joined: 07 Dec 2014
Posts: 1197
Find m if the sum of the consecutive integers from -16 to m, inclusive  [#permalink]

Show Tags

New post 12 Jan 2019, 21:26
Mina Satti wrote:
Find m if the sum of the consecutive integers from -16 to m, inclusive is 74.


A) 17
B) 18
C) 19
D) 20
E) 21



[(-16+m)/2](17+m)=74→
m^2+m-420=0→
x=20
D
GMAT Club Bot
Find m if the sum of the consecutive integers from -16 to m, inclusive   [#permalink] 12 Jan 2019, 21:26
Display posts from previous: Sort by

Find m if the sum of the consecutive integers from -16 to m, inclusive

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


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