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

Redeem
TTP OnDemand GMAT Video Course
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
Start Free 5-Day Trial Read 559 Reviews →

radical sign question

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Problem Solving |
Master | Next Rank: 500 Posts
Posts: 392
Joined: Thu Jan 15, 2009 12:52 pm
Location: New Jersey
Thanked: 76 times

by truplayer256 » Wed Jul 22, 2009 10:22 am
3*sqrt(x+y)=c^8

sqrt(x+y)=c^8/3

Square both sides to get:

x+y=(c^8/3)^(2)=c^16/9
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Junior | Next Rank: 30 Posts
Posts: 10
Joined: Sat Mar 14, 2009 8:18 am

ans

by beter2jump » Wed Jul 22, 2009 10:59 am
the ans to this question was

x+y = C^18
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 392
Joined: Thu Jan 15, 2009 12:52 pm
Location: New Jersey
Thanked: 76 times

by truplayer256 » Thu Jul 23, 2009 9:45 am
I'm pretty sure that the answer is not x+y=c^18 unless you typed the question incorrectly. May I know the source of this question?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Junior | Next Rank: 30 Posts
Posts: 10
Joined: Sat Mar 14, 2009 8:18 am

question

by beter2jump » Thu Jul 23, 2009 9:58 am
as i cant type the radical sign the qn seems awkward.

in fact its not 3*sqrt(x+y), the three is on the left of sqrt on the sqrt sign.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 392
Joined: Thu Jan 15, 2009 12:52 pm
Location: New Jersey
Thanked: 76 times

by truplayer256 » Thu Jul 23, 2009 11:15 am
as i cant type the radical sign the qn seems awkward.

in fact its not 3*sqrt(x+y), the three is on the left of sqrt on the sqrt sign.
Oh, okay. This makes a lot more sense now :)

So the question is really:

cubic root of (x+y)= c^8

All we do here is take the cube of both sides:

x+y=(c^8)^(3)=c^24... It still doesn't match the OA. Why's this?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
GMAT Instructor
Posts: 3225
Joined: Tue Jan 08, 2008 2:40 pmFollowed by: 614 members
Location: Toronto
Thanked: 1710 times
GMAT Score:800

by Stuart@KaplanGMAT » Thu Jul 23, 2009 1:08 pm
truplayer256 wrote:
as i cant type the radical sign the qn seems awkward.

in fact its not 3*sqrt(x+y), the three is on the left of sqrt on the sqrt sign.
Oh, okay. This makes a lot more sense now :)

So the question is really:

cubic root of (x+y)= c^8

All we do here is take the cube of both sides:

x+y=(c^8)^(3)=c^24... It still doesn't match the OA. Why's this?
I agree - are you sure that the original question didn't read c^6 instead of c^8?
Image

Stuart Kovinsky | Kaplan GMAT Faculty | Toronto

Kaplan Exclusive: The Official Test Day Experience | Ready to Take a Free Practice Test? | Kaplan/Beat the GMAT Member Discount
BTG100 for $100 off a full course
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Junior | Next Rank: 30 Posts
Posts: 10
Joined: Sat Mar 14, 2009 8:18 am

right

by beter2jump » Thu Jul 23, 2009 1:48 pm
I don't know as i noted this problem during a review quickly ...

My confusion is cleared though, as i was not sure how to remove cube root from one side , which the ans have demonstrated ...

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