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 →

Problem Solving for 780+ Aspirants.

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Legendary Member
Posts: 891
Joined: Sat Aug 16, 2008 4:21 amFollowed by: 1 member
Thanked: 27 times
GMAT Score:660(

by 4meonly » Tue Feb 10, 2009 7:21 am
<ACB is 60?
prolong AP for the length of PB and make a point O
triangles APB anf trg CPO are simalar
triangles ACP anf trg POB are simalar
and so on... I am stuck :(
Attachments
1251235.JPG
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 66
Joined: Fri Oct 31, 2008 2:41 pm
Location: London, UK
Thanked: 5 times
GMAT Score:770

by cjb » Tue Feb 10, 2009 8:24 am
4meonly wrote: triangles APB anf trg CPO are simalar
triangles ACP anf trg POB are simalar
I don't think this is true - you know that PO = PB, but you don't know that PA = PC.
80% of success is showing up -- Woody Allen
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Newbie | Next Rank: 10 Posts
Posts: 6
Joined: Tue Feb 10, 2009 1:08 pm
Location: Brooklyn

by utibay » Wed Feb 11, 2009 1:36 am
sureshbala wrote:Folks, here is the next apple.....

Image

In the above figure, PB/PC = 1/2 LCBA = 45° while LAPC = 60°. Find LACB.
This was difficult, and took a while, but I think I got it.

Since <APB + 60 = 180, <APB = 120, which means that <PAB = 15

PB:PC is 1:2... let's assign the value X to PB, meaning that PC = 2X

The ratio of any given angle in a triangle to 180 is equivalent to the ratio of the length that angle's opposite side to triangle's perimeter.

The ratio, <PAB:<PBA:<APB = 15:45:120, or 1:3:8. Following that ratio and the fact that PB=X and is opposite <PAB, AP=3X (opposite of <PBA), and AB=8X (opposite of <APB). (To further that, you can say that <PAB=X, <PBA=3X and <APB=8X, where X=15)

Since <CAP + <ACP + 60 = 180, <CAP + <ACP = 120.

Since the opposite side of <ACP is AP and AP=3X, <ACP=3X; and since the opposite side of <CAP is CP and CP=2X, <CAP=2X and the ratio of <ACP to <CAP is 3:2.

Taking that, you can rewrite the equation, <CAP + <ACP = 120, as 2X + 3X = 120:

2X + 3X = 120
5X = 120
X = 120/5 = 24

Since, <ACP = 3X, <ACP = 24*3 = 72

<ACB = <ACP = 72
"Being ignorant is not so much a shame, as being unwilling to learn." -Benjamin Franklin
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 891
Joined: Sat Aug 16, 2008 4:21 amFollowed by: 1 member
Thanked: 27 times
GMAT Score:660(

by 4meonly » Wed Feb 11, 2009 3:06 am
utibay wrote: The ratio of any given angle in a triangle to 180 is equivalent to the ratio of the length that angle's opposite side to triangle's perimeter.

The ratio, <PAB:<PBA:<APB = 15:45:120, or 1:3:8. Following that ratio and the fact that PB=X and is opposite <PAB, AP=3X
Means that on 30-60-90 angles triangle ratio of angles is 1:2:3, BUT thr ratio of sides is 1:2:sqrt3
according to your reasoning this ration should be 1:2:3
What do you think?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 891
Joined: Sat Aug 16, 2008 4:21 amFollowed by: 1 member
Thanked: 27 times
GMAT Score:660(

by 4meonly » Wed Feb 11, 2009 8:59 am
sureshbala, where are you?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Master | Next Rank: 500 Posts
Posts: 319
Joined: Wed Feb 04, 2009 10:32 amFollowed by: 9 members
Location: Delhi
Thanked: 84 times

by sureshbala » Wed Feb 11, 2009 11:33 am
Folks, finally here is the solution....Thought of being more clear on this problem, so uploaded the image....Have a look at this....


Image
Last edited by sureshbala on Thu Feb 12, 2009 10:22 pm, edited 1 time in total.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 66
Joined: Fri Oct 31, 2008 2:41 pm
Location: London, UK
Thanked: 5 times
GMAT Score:770

by cjb » Wed Feb 11, 2009 5:49 pm
Hi Sureshbala - I followed all of that to the point where you wrote:

AD = DB, so DC = AD

I don't follow the logic there - how do we know that DC = AD?

Love the rest of the puzzle though. It's kind of elegant. Have you got more?
80% of success is showing up -- Woody Allen
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 158
Joined: Tue Sep 30, 2008 8:47 amFollowed by: 1 member
Thanked: 23 times
GMAT Score:660

by DeepakR » Wed Feb 11, 2009 6:04 pm
We know that DPB=120 so DBP=PDB=30 each. Since ABP=45 and DBP=30 we get DBA=15 already BAD=15 hence ADB is isoceles triangle. Hence AD=DB. Its already proved that DB=DC hence AD=DC.

- Deepak
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Newbie | Next Rank: 10 Posts
Posts: 7
Joined: Thu Dec 25, 2008 3:15 pm

Awesome Question!

by sameke » Wed Feb 11, 2009 8:38 pm
Guys,
I first got 45 degree angle but could not prove it. But then I remembered simple circle properties. Yep, the answer is right. Thanks.

Keep posting similar questions!
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Master | Next Rank: 500 Posts
Posts: 319
Joined: Wed Feb 04, 2009 10:32 amFollowed by: 9 members
Location: Delhi
Thanked: 84 times

by sureshbala » Wed Feb 11, 2009 9:26 pm
Folks, as a content developer I prepare these questions and I am sure you are going to like these problems...any feed back is welcome.....
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Site Admin
Posts: 2567
Joined: Thu Jan 01, 2009 10:05 amFollowed by: 550 members
Thanked: 712 times
GMAT Score:770

by DanaJ » Wed Feb 11, 2009 11:56 pm
Although your questions are challenging, I've never seen this type of problems on GMAT. IMHO, your questions are more about good (and pretty hard) geometry practice than the GMAT itself.
Last edited by DanaJ on Thu Feb 12, 2009 1:04 am, edited 1 time in total.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 2134
Joined: Mon Oct 20, 2008 11:26 pmFollowed by: 25 members
Thanked: 237 times
GMAT Score:730

by logitech » Thu Feb 12, 2009 12:38 am
How to waste time 101

Come on guys, let's get back to Earth. We are not studying for Calculus in the college. This is a GMAT test and concepts are very VERY straightforward.
LGTCH
---------------------
"DON'T LET ANYONE STEAL YOUR DREAM!"
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Master | Next Rank: 500 Posts
Posts: 319
Joined: Wed Feb 04, 2009 10:32 amFollowed by: 9 members
Location: Delhi
Thanked: 84 times

by sureshbala » Thu Feb 12, 2009 1:28 am
Keeping in mind the feedback(I agree to the point that these questions are a bit tough but at the same time much within the basic concepts) that I got, here is the next one...

Edusoft, a software firm has engaged certain number of men to finish a project in the stipulated time. But after working for 14 days, 1/4 of them have left and to complete the remaining project the remaining members have taken as many days as the initial number of men would have taken to complete the entire project. In how many days was the project completed?

A. 48 B. 60 C. 56 D. 40 E. None of these
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 137
Joined: Thu Jan 08, 2009 1:27 am
Thanked: 7 times

by welcome » Thu Feb 12, 2009 1:30 am
IMHO this can be a good question for entrance exam of some engineeing test but not GMAT. GMAT is not for making you Aaryabhatta it is to judge whether you can easily understand the business calculations.
Shubham.
590 >> 630 >> 640 >> 610 >> 600 >> 640 >> 590 >> 640 >> 590 >> 590
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Junior | Next Rank: 30 Posts
Posts: 29
Joined: Sun Feb 08, 2009 11:29 am
Thanked: 3 times

by ven4gmat » Thu Feb 12, 2009 1:50 am
welcome wrote:IMHO this can be a good question for entrance exam of some engineeing test but not GMAT. GMAT is not for making you Aaryabhatta it is to judge whether you can easily understand the business calculations.
I agree that these questions are tough but as pointed out by sureshbala these are based only on the baisc concepts and not beyond that. I think Aaryabhatta math is much ahead of this. I seriously feel that if these questions are asked in terms of DS (where we don't need to find the answer but in order to crack these questions we need the concepts) some of us for sure would agree to the point that they may appear in the exam at least for a 780+ aspirant. sureshbala why don't you start a DS thread?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply