BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course
Redeem
Featured Course
Target Test Prep GMAT OnDemand
Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.
- 715+ score guarantee — highest in the industry (99th percentile)
- 52 chapters · 1,500+ lessons · 4,000+ practice questions
- 400 hours of video · 1,500+ instructor-led HD smartboard lessons
- 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
- 24/7 live support + weekly Zoom office hours with GMAT instructors
- TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
- 1,200+ flashcards + AI-powered study assistant & daily calendar
- OnDemand, LiveTeach & GMAT Bootcamp formats available
- Also: GRE, SAT Math & Executive Assessment courses
- MBA Admissions Consulting now available
- 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
- 200,000+ students served
- 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★
5.0
(559 reviews)
130-pt guarantee
$0 to start
then $127/mo
DS question on Sum of consecutive postive integers
Source: Beat The GMAT — Data Sufficiency |
I agree with Calista
The sum of n consecutive positive integers is 45. What is the value of n?
(1) n is even
Now 45 is an odd nos
so if n is even, it must have half even nos & half odd nos which will when summed up will lead to an odd nos, there are many possibilities like 22,23 5,6,7,8,9,10 etc INSUFF
(2) n < 9
again the above possibilities will arise and we can have odd value of n also
as 14,15,16 INSUFF
Combine again n can assume odd as well as even vals below 9 INSUFF
E
The sum of n consecutive positive integers is 45. What is the value of n?
(1) n is even
Now 45 is an odd nos
so if n is even, it must have half even nos & half odd nos which will when summed up will lead to an odd nos, there are many possibilities like 22,23 5,6,7,8,9,10 etc INSUFF
(2) n < 9
again the above possibilities will arise and we can have odd value of n also
as 14,15,16 INSUFF
Combine again n can assume odd as well as even vals below 9 INSUFF
E
Regards
Samir
Samir
The sum of n consecutive positive integers is 45. What is the value of n?
(1) n is even
(2) n < 9
22 + 23 = 45; here n = 2 which is even and less than 9.
5+6+7+8+9+10 = 45; here n = 6 which is even and less than 9.
Simple. Answer must be E and hence MGMAT is wrong.
Calista.
(1) n is even
(2) n < 9
22 + 23 = 45; here n = 2 which is even and less than 9.
5+6+7+8+9+10 = 45; here n = 6 which is even and less than 9.
Simple. Answer must be E and hence MGMAT is wrong.
Calista.
The Most easy way to solve this equation is
1) as the elements are consecutive integer they are in AP
hence Sum of n consecutive elements is = a(2a+n-1)/2
Hence we can form the Equation as
a(2a+n-1)/2 = 45
Where a--- the First integer in the series.
n-- no of integers in the series.
as it is equation of two variables unless you get the value of the a we can solve the problems.Hence both the conditions are insufficient.
E
Hope this will help you understand easily
1) as the elements are consecutive integer they are in AP
hence Sum of n consecutive elements is = a(2a+n-1)/2
Hence we can form the Equation as
a(2a+n-1)/2 = 45
Where a--- the First integer in the series.
n-- no of integers in the series.
as it is equation of two variables unless you get the value of the a we can solve the problems.Hence both the conditions are insufficient.
E
Hope this will help you understand easily
Auzbee,
I checked the MGMAT explanation just now, they too say that the answer is E.
However in your first post, you gave the OA as D.
That's why this confusion.
Calista.
I checked the MGMAT explanation just now, they too say that the answer is E.
However in your first post, you gave the OA as D.
That's why this confusion.
Calista.
[quote]Auzbee,
I checked the MGMAT explanation just now, they too say that the answer is E.
However in your first post, you gave the OA as D.
That's why this confusion.
[/quote]
My apologies for being in a haste while replying. Let me correct my previous post on this thread.
I checked the MGMAT explanation just now, they too say that the answer is E.
However in your first post, you gave the OA as D.
That's why this confusion.
[/quote]
My apologies for being in a haste while replying. Let me correct my previous post on this thread.
