• Get 300+ Practice Questions

Available with Beat the GMAT members only code

• Magoosh
Study with Magoosh GMAT prep

Available with Beat the GMAT members only code

• 5-Day Free Trial
5-day free, full-access trial TTP Quant

Available with Beat the GMAT members only code

• Free Practice Test & Review
How would you score if you took the GMAT

Available with Beat the GMAT members only code

• Free Veritas GMAT Class
Experience Lesson 1 Live Free

Available with Beat the GMAT members only code

• Award-winning private GMAT tutoring
Register now and save up to \$200

Available with Beat the GMAT members only code

• Free Trial & Practice Exam
BEAT THE GMAT EXCLUSIVE

Available with Beat the GMAT members only code

• 1 Hour Free
BEAT THE GMAT EXCLUSIVE

Available with Beat the GMAT members only code

• 5 Day FREE Trial
Study Smarter, Not Harder

Available with Beat the GMAT members only code

500 ds

This topic has 6 member replies
dunkin77 Master | Next Rank: 500 Posts
Joined
01 Apr 2007
Posted:
269 messages

500 ds

Wed Apr 04, 2007 2:00 pm
Elapsed Time: 00:00
• Lap #[LAPCOUNT] ([LAPTIME])
Hi,

Pls see the attached.

I thought the answer was C) but turned out to be B).

Can anyone pls explain? thanks!
Attachments

Need free GMAT or MBA advice from an expert? Register for Beat The GMAT now and post your question in these forums!
jayhawk2001 Community Manager
Joined
28 Jan 2007
Posted:
789 messages
Followed by:
1 members
Thanked:
29 times
Wed Apr 04, 2007 9:12 pm
We have to use properties of similar triangles here. Draw lines
from B and C to the ground. Lets call these points D and E respectively
on the ground. BD and CE are parallel

We are given that AB = BC.

(2) says that BD = 5. We can use properties of similar triangles now.
BD / CE = AB / AC. We can hence compute CE

So B is the correct answer.

dunkin77 Master | Next Rank: 500 Posts
Joined
01 Apr 2007
Posted:
269 messages
Thu Apr 05, 2007 7:50 am
Thanks for explanation Jay.

I am still a bit confused cause we only know AB=AC and BD=5,
so, BD / CE = AB / AC (let's say AB=AC=3)

5 / CE = 3 / 3

5/CE=1

CE=5..........??

I would appreciate it if you could explain a bit more... thanks again for your help!!

gabriel Legendary Member
Joined
20 Dec 2006
Posted:
986 messages
Followed by:
1 members
Thanked:
51 times
Thu Apr 05, 2007 10:01 am
dunkin77 wrote:
Thanks for explanation Jay.

I am still a bit confused cause we only know AB=AC and BD=5,
so, BD / CE = AB / AC (let's say AB=AC=3)

5 / CE = 3 / 3

5/CE=1

CE=5..........??

I would appreciate it if you could explain a bit more... thanks again for your help!!
dunkin u have got evrything right except for the part that AB= AC ... AB is actually = BC ... therefore AC=2AB ... so we have 5/CE = AB/AC .... 5/CE = 1/2 .. therefore CE = 10 .. hence the answer is B

vk.neni Junior | Next Rank: 30 Posts
Joined
27 Mar 2007
Posted:
12 messages
Thu Apr 05, 2007 10:52 am
Hi,
Couldn't we solve this using information in (i) x=30? With this info the small triangle (ABD) becomes a 30-60-90 and we know the length of one of the sides, so we can figure the other two sides. Once, we've this info, we can use the similar triangle method to solve it. So, the answer would be D.

myprepgmat Newbie | Next Rank: 10 Posts
Joined
10 Mar 2007
Posted:
2 messages
Sat Apr 07, 2007 5:06 am
Ans is B

I'll explain...

Let the height of point B is h and the point is H. Let the length of seesaw ie AC is 2d..

Now draw perpendicular lines to ground from point B and C. Let they intersect at ground at D ( from Point B) & E(point C).

Now we will get two similar triangles.. ie ABD and ACE..

we have BD/AB = CE/AC

ie h/d= H/2d given AB=BC we assumed AC=2d

i.e. h=H/2

given h=5ft

therefore H=10ft

case 1 doesnot give any unique value as the length of AC or height of the point B is not given.

gabriel Legendary Member
Joined
20 Dec 2006
Posted:
986 messages
Followed by:
1 members
Thanked:
51 times
Sat Apr 07, 2007 9:51 am
vk.neni wrote:
Hi,
Couldn't we solve this using information in (i) x=30? With this info the small triangle (ABD) becomes a 30-60-90 and we know the length of one of the sides, so we can figure the other two sides. Once, we've this info, we can use the similar triangle method to solve it. So, the answer would be D.
dude one of the most basic mistake for a DS... carrying information from one statement to the other .. the length of the side is mentioned only in the second statement.. so cant use it for the first ..

Best Conversation Starters

1 Vincen 180 topics
2 lheiannie07 65 topics
3 Roland2rule 49 topics
4 ardz24 40 topics
5 LUANDATO 16 topics
See More Top Beat The GMAT Members...

Most Active Experts

1 Brent@GMATPrepNow

GMAT Prep Now Teacher

146 posts
2 Rich.C@EMPOWERgma...

EMPOWERgmat

103 posts
3 GMATGuruNY

The Princeton Review Teacher

100 posts
4 EconomistGMATTutor

The Economist GMAT Tutor

92 posts
5 Jay@ManhattanReview

Manhattan Review

79 posts
See More Top Beat The GMAT Experts