BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

★★★★★5.0559 reviews
GMATLiveTeach 7 seats left
Chris Peckover
NEXT LIVE COHORT

Oct 13 to Jan 7, 2027

with Chris Peckover

Schedule
Tue, Thu · 8:00 to 10:00 PM ET
Included
40 live hours + 6 months of GMAT OnDemand
  • Live instruction and real-time questions
  • Class recordings and assigned practice
View class & enroll
Limited cohort · enrollment openTarget Test Prep
EALiveTeach 5 seats left
Logan Thompson
EXECUTIVE ASSESSMENT

Sep 6 to Dec 6, 2026

with Logan Thompson

Schedule
Sun · 9:30 AM to 12:30 PM ET
Included
Live EA class + 6 months of EA OnDemand
  • Expert-led weekly online sessions
  • EA Masterclass access between classes
View EA class & enroll
Limited cohort · enrollment openTarget Test Prep
GMATOnDemand Start anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

130-point score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions
Start free 5-day trial
Read 559 reviewsTarget Test Prep

Compare the format, schedule, and included access before enrolling. Prices and seat counts shown reflect the supplied offer details.

An odd number added to itself an odd number of times yields

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Legendary Member
Posts: 2898
Joined: Thu Sep 07, 2017 2:49 pmFollowed by: 5 members
Thanked: 6 times
by Vincen » Fri Sep 29, 2017 5:52 pm
An odd number added to itself an odd number of times yields

(A) an odd number
(B) an even number
(C) a prime number
(D) a positive number
(E) a perfect square

The OA is A.

I did it for a particular number, but is there any way to prove it in general?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3008
Joined: Mon Aug 22, 2016 6:19 amFollowed by: 34 members
Location: Grand Central / New York
Thanked: 470 times

by Jay@ManhattanReview » Sun Oct 01, 2017 9:29 pm
Vincen wrote:An odd number added to itself an odd number of times yields

(A) an odd number
(B) an even number
(C) a prime number
(D) a positive number
(E) a perfect square

The OA is A.

I did it for a particular number, but is there any way to prove it in general?
Say an odd number is 3, and it is added 5 times (odd number of times) to itself (3).

Thus, the result = 3 + 3 + 3 + 3 + 3 = 15, and odd number.

An algebraic approach:

Say an odd number is n and it is added m times, where m is also an odd number.

Thus, the result = n + n + n + ... m times = m*n = Odd * Odd = Odd.

The question is not drafted well. The correct should be: An odd number added to itself an odd number of times must yield

Otherwise, except option B, all the options can also be correct, though not always. For example, if 1 is added 3 times, the result is a prime and a positive number. Similarly, if 3 is added 3 times, the result is a perfect square number.

Thus, except B, all option could be correct; however, only A must be correct.

Hope this helps!

-Jay

Download free ebook: Manhattan Review GMAT Quantitative Question Bank Guide
_________________
Manhattan Review GMAT Prep

Locations: New York | Barcelona | Manila | Melbourne | and many more...

Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
GMAT Instructor
Posts: 555
Joined: Wed Oct 04, 2017 4:18 pmFollowed by: 12 members
Thanked: 180 times

by EconomistGMATTutor » Sun Oct 08, 2017 8:29 am
Vincen wrote:An odd number added to itself an odd number of times yields

(A) an odd number
(B) an even number
(C) a prime number
(D) a positive number
(E) a perfect square

The OA is A.

I did it for a particular number, but is there any way to prove it in general?
Hi Vincen,
Let's take a look at your question.

The question states that,
An odd number added to itself an odd number of times.
We know that an odd number can be represented as 2n + 1 in general.

An odd number added to itself 3 times:
(2n+1)+(2n+1)+(2n+1) = 3(2n + 1)

An odd number added to itself 5 times:
(2n+1)+(2n+1)+(2n+1)+(2n+1)+(2n+1) = 5(2n + 1)
...
An odd number added to itself an odd number of times let's say for (2n+3) times
(2n+1)+(2n+1)+(2n+1)+(2n+1)+...+(2n+1) = (2n+3)(2n+1)

We know that (2n+3) is an odd number and (2n+1) is an odd number.
The product of two odd numbers is an odd number always.
Therefore, (2n+3)(2n+1) is an odd number.

Option A is correct.

I am available if you'd like any followup.
GMAT Prep From The Economist
We offer 70+ point score improvement money back guarantee.
Our average student improves 98 points.

Image
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 8177
Joined: Sat Apr 25, 2015 10:56 amFollowed by: 29 members
Location: Los Angeles, CA
Thanked: 43 times

Re: An odd number added to itself an odd number of times yields

by Scott@TargetTestPrep » Sun Feb 02, 2020 10:15 am
Vincen wrote: ↑
Fri Sep 29, 2017 5:52 pm
 An odd number added to itself an odd number of times yields

(A) an odd number
(B) an even number
(C) a prime number
(D) a positive number
(E) a perfect square

The OA is A.

I did it for a particular number, but is there any way to prove it in general?
1 added to itself 3 times is:

1 + 1 + 1 = 3

3 added to itself 5 times is:

3 + 3 + 3 + 3 + 3 = 15

Thus, we see the result must be an odd number.

Answer: A

Scott Woodbury-Stewart
Founder and CEO
[email protected]

Image

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews

ImageImage
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1