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

Help me solv this?

Expert replies
by disturbedmimi » Thu Sep 06, 2012 7:01 pm
If both x and y are positive integers then which of the following expressions must also be even?
i.. y^x-1
ii.y-1
iii. x/2

(a) i only
(b) ii only
(c) iii. only
(d) i and iii only
(e) i, ii, and iii
Join the discussion
Source: — Problem Solving |

by everything's eventual » Thu Sep 06, 2012 7:30 pm
I feel that some info is missing here.

Lets take (ii) and (iii) into consideration first.

(ii) will be even if y is odd and odd is y is even.

(iii) will be even if x is even and odd is x is odd.

Now considering(i)

y ^ (x-1)

Consider x as odd ( say 3) and y as even ( say 2). So after substituting in the equation we get value as 4 viz even. Now consider, x as even ( say 2) and y as odd ( say 3). Now we get value as 3 viz odd.

According to my solution none of them "must" be even.
Join the discussion

by everything's eventual » Thu Sep 06, 2012 7:32 pm
I think that the problem states that both x and y are even positive integers. In this case the answer is (d) : (i) and (iii) only
Join the discussion

by Shalabh's Quants » Fri Sep 07, 2012 7:15 am
everything's eventual wrote:I think that the problem states that both x and y are even positive integers. In this case the answer is (d) : (i) and (iii) only
(iii) is not necessarily an even. Take x=6, then x/2 would be Odd.
Shalabh Jain,
e-GMAT Instructor
Join the discussion

by Brent@GMATPrepNow » Fri Sep 07, 2012 8:46 am
disturbedmimi wrote:If both x and y are positive integers then which of the following expressions must also be even?
i.. y^x-1
ii.y-1
iii. x/2

(a) i only
(b) ii only
(c) iii. only
(d) i and iii only
(e) i, ii, and iii
This question could use some clarification before we try to answer it.

First, there's some uncertainty with ". . . which of the following expressions must also be even?"
Also?
Is one or both of the given variables (x, y) supposed to be even?

Second, there's some possible ambiguity with the first expresson: y^x-1
Does this mean (y^x) - 1 or y^(x-1)?
Some brackets (or even some spaces) would help prevent any ambiguity.

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Join the discussion

by everything's eventual » Fri Sep 07, 2012 9:14 am
@ Shalabh...yes very silly of me...in that case we have only (i)
Join the discussion