Live GMAT classes with Target Test Prep start Nov 21 and Nov 22. First class free.

See classes
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.

Newsweek Readers’ Choice Awards 2026 winner: Target Test Prep, #1 Test Prep

Target Test Prep was voted #1 Best Test Prep in the 2026 Newsweek Readers’ Choice™ Awards.

★★★★★5.0563 reviews
GMATLiveTeachStarts Nov 22
Josh Braslow, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Josh Braslow, 20+ years in test prep

Nov 22 · Josh Braslow
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes + 6 months of TTP OnDemand
  • Attend the first class for free
  • Every class is recorded, so you never fall behind
View classes & enroll
Limited seats availableTarget Test Prep
EALiveTeachOnDemandStart anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

EXECUTIVE ASSESSMENT

with

165+ EA score guarantee
$05-day trial no automatic billing
Schedule
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll Start free 5-day trial
Limited cohort · enrollment openTrial includes full course accessTarget Test Prep
GMATOnDemandStart anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions

challenge number properties ........ continued

Expert replies
by Night reader » Mon Dec 13, 2010 10:29 pm
If n = 8zy, where z and y are distinct prime numbers greater than 2, how many different positive even divisors does n have, excluding n ?

(A) Nine
(B) Ten
(C) Eleven
(D) Twelve
(E) Thirteen
Join the discussion
Source: — Problem Solving |

by Rahul@gurome » Mon Dec 13, 2010 10:41 pm
So n = 2^3 * y^1 * z^1.
So total number of divisors it will have will be 4*2*2 = 16.
Number of odd divisors is 2*2 = 4.
So number of even divisors is 16 - 4 = 12.
This includes n.
So excluding n, we have 12 - 1 = 11 even divisors.
The correct answer is (C).
Rahul Lakhani
Quant Expert
Gurome, Inc.
https://www.GuroMe.com
On MBA sabbatical (at ISB) for 2011-12 - will stay active as time permits
1-800-566-4043 (USA)
+91-99201 32411 (India)
Join the discussion

by junegmat221 » Tue Dec 14, 2010 12:08 am
@Rahul,
this method takes odd factors namely
2 to the power 0 ,
y to the power 0 (since y is odd and 2 is the only even prime)
y to the power 1
z to the power 0 (since z is odd and 2 is the only even prime)
z to the power 1

I thought these five would negate the Total number of factors(16) and result in 11...
Am i doing anything wrong here..????


I had doubts on this and Rather plugged in the smalles values in y and z namely 3 and 5 and computed the even divisors of
8 * 3 * 5 which are 2,4,6,8,10,12,20,30,40,50,60 which comes to eleven..But this method really kills my time..
Join the discussion

by Rahul@gurome » Tue Dec 14, 2010 12:25 am
junegmat221 wrote:@Rahul,
this method takes odd factors namely
2 to the power 0 ,
y to the power 0 (since y is odd and 2 is the only even prime)
y to the power 1
z to the power 0 (since z is odd and 2 is the only even prime)
z to the power 1

I thought these five would negate the Total number of factors(16) and result in 11...
Am i doing anything wrong here..????


I had doubts on this and Rather plugged in the smalles values in y and z namely 3 and 5 and computed the even divisors of
8 * 3 * 5 which are 2,4,6,8,10,12,20,30,40,50,60 which comes to eleven..But this method really kills my time..
2^0, y^0 and z^0 are all giving the same value 1.
So they cannot be taken as distinct odd factors.
Distinct odd factors will be 1, y, z and y*z.
They will be 4 in number.
Rahul Lakhani
Quant Expert
Gurome, Inc.
https://www.GuroMe.com
On MBA sabbatical (at ISB) for 2011-12 - will stay active as time permits
1-800-566-4043 (USA)
+91-99201 32411 (India)
Join the discussion