January 22, 2019 January 22, 2019 10:00 PM PST 11:00 PM PST In case you didn’t notice, we recently held the 1st ever GMAT game show and it was awesome! See who won a full GMAT course, and register to the next one. January 26, 2019 January 26, 2019 07:00 AM PST 09:00 AM PST Attend this webinar to learn how to leverage Meaning and Logic to solve the most challenging Sentence Correction Questions.
Author 
Message 
TAGS:

Hide Tags

Manager
Joined: 11 Jan 2006
Posts: 221
Location: Arkansas, US
WE 1: 2.5 yrs in manufacturing

In the figure above, line AC represents a seesaw that is
[#permalink]
Show Tags
Updated on: 29 Nov 2013, 01:25
Question Stats:
53% (01:09) correct 47% (01:06) wrong based on 369 sessions
HideShow timer Statistics
Attachment:
Untitled.png [ 1.22 KiB  Viewed 5455 times ]
In the figure above, line AC represents a seesaw that is touching level ground at point A. If B is the midpoint of AC, how far above the ground is point C? (1) x = 30 (2) Point B is 5 feet above the ground.
Official Answer and Stats are available only to registered users. Register/ Login.
Attachments
fig1.doc [20.5 KiB]
Downloaded 161 times
_________________
ARISE AWAKE AND REST NOT UNTIL THE GOAL IS ACHIEVED
Originally posted by Raghavender on 03 Oct 2006, 04:34.
Last edited by Bunuel on 29 Nov 2013, 01:25, edited 1 time in total.
Edited the question and added the OA.




Intern
Joined: 14 Jul 2005
Posts: 44
Location: California

Answer is B.
Statement 2 alone is suff.
lets say: BA= x
then CA = 2x (since B is the mid point of CA)
Triangle ACD(D is the point where the perpendicular dropped from C touches the ground) is similar to triangle ABE(E is the point where the perpendicular dropped from C touches the ground).
Therefore x/5=2x/z
or z=10




Director
Joined: 06 Sep 2006
Posts: 670

20. In the figure above, line AC represents a seesaw that is touching level ground at point A. If B is the midpoint of AC, how far above the ground is point C?
(1) x = 30
(2) Point B is 5 feet above the ground.
A & B are unsufficient.
Combining
Sin 30(degree) = 5/AB
so AB can be determine and hence AC, since AC=2AB.
If we draw a perpendicula from line A which touches point C and call that point (on line A) D.
So, Sin 30 = AD/2AB
Answer is C.



Director
Joined: 23 Jun 2005
Posts: 783

This one had me stumped. But, B it is, as others have explained before.



Senior Manager
Joined: 28 Aug 2006
Posts: 301

[#permalink]
Show Tags
Updated on: 25 Sep 2008, 00:30
Originally posted by cicerone on 05 Oct 2006, 00:03.
Last edited by cicerone on 25 Sep 2008, 00:30, edited 1 time in total.



Manager
Joined: 11 Jan 2006
Posts: 221
Location: Arkansas, US
WE 1: 2.5 yrs in manufacturing

Gud explanation 800_gal...
Thanks for that..hahaa..completely forgot about the similar triangles properties...gotto revise it now...
_________________
ARISE AWAKE AND REST NOT UNTIL THE GOAL IS ACHIEVED



SVP
Joined: 06 Sep 2013
Posts: 1705
Concentration: Finance

Re: In the figure above, line AC represents a seesaw that is
[#permalink]
Show Tags
28 Nov 2013, 13:57
Raghavender wrote: 20. In the figure above, line AC represents a seesaw that is touching level ground at point A. If B is the midpoint of AC, how far above the ground is point C? (1) x = 30 (2) Point B is 5 feet above the ground. Is there anyway someone can put the picture on the problem so we don't have to open it every time? Much appreciated! Cheers J



Math Expert
Joined: 02 Sep 2009
Posts: 52387

Re: In the figure above, line AC represents a seesaw that is
[#permalink]
Show Tags
29 Nov 2013, 01:25



eGMAT Representative
Joined: 04 Jan 2015
Posts: 2457

Re: In the figure above, line AC represents a seesaw that is
[#permalink]
Show Tags
06 May 2015, 02:02
Hi All, For those of you who are not comfortable with the concept of similar triangles and its application, this question can be solved using application of simple trigonometric ratios.In triangle ABD which is right angled at D, we can use \(Sin x = \frac{BD}{AB.}\) Similarly, in triangle ACE which is right angled at E, we can use \(Sin x = \frac{CE}{AC}\) From the above two equations, we can write \(\frac{BD}{AB} = \frac{CE}{AC}\) i.e. \(CE = \frac{(BD * AC)}{AB.}\) Since \(AC = 2AB\), we can write \(CE = 2BD\). So, for finding the height of point C from the ground we just need to know the height of point B from the ground. We see that stII provides us the height of B. Thus statementII alone is sufficient to answer the question. You can try out a similar question at asquirrelclimbsastraightwirefrompointatopointcifbisthe195315.html#p1517662Hope its clear! Regards Harsh
_________________
Register for free sessions Number Properties  Algebra Quant Workshop
Success Stories Guillermo's Success Story  Carrie's Success Story
Ace GMAT quant Articles and Question to reach Q51  Question of the week
Must Read Articles Number Properties – Even Odd  LCM GCD  Statistics1  Statistics2  Remainders1  Remainders2 Word Problems – Percentage 1  Percentage 2  Time and Work 1  Time and Work 2  Time, Speed and Distance 1  Time, Speed and Distance 2 Advanced Topics Permutation and Combination 1  Permutation and Combination 2  Permutation and Combination 3  Probability Geometry Triangles 1  Triangles 2  Triangles 3  Common Mistakes in Geometry Algebra Wavy line  Inequalities Practice Questions Number Properties 1  Number Properties 2  Algebra 1  Geometry  Prime Numbers  Absolute value equations  Sets
 '4 out of Top 5' Instructors on gmatclub  70 point improvement guarantee  www.egmat.com



Manager
Joined: 07 Apr 2015
Posts: 164

In the figure above, line AC represents a seesaw that is
[#permalink]
Show Tags
25 Jul 2015, 04:40
What i don't get is why we can assume that the two triangles are similar just because AB = BC?
I mean it looks similar, but why can we apply that?



CEO
Joined: 20 Mar 2014
Posts: 2636
Concentration: Finance, Strategy
GPA: 3.7
WE: Engineering (Aerospace and Defense)

In the figure above, line AC represents a seesaw that is
[#permalink]
Show Tags
25 Jul 2015, 05:01
noTh1ng wrote: What i don't get is why we can assume that the two triangles are similar just because AB = BC?
I mean i looks similar, but why can we apply that? Refer to the attached figure for description of the points. BD and CE are perpendicular to AE. So, in triangles ABD and ACE, angle A is common angle to both the triangles, \(\angle{ADB} = \angle{AEC} = 90\) and \(\angle {ABD} = \angle{ACE}\) (BD  CE) Thus triangles ABD ad ACE are similar by AA (or angle angle similarity theorem) Thus, by similarity AB/ AC = BD / CE Given BD = 5 and AB = 0.5*AC Thus CE = 10. Hence, Statement 2 is sufficient. Per statement 1, x =30 does not provide us any other useful information. Thus B is the correct answer. Hope this helps.
Attachments
Similar triangles.jpg [ 11.3 KiB  Viewed 3609 times ]



Manager
Joined: 09 Jan 2013
Posts: 75
Concentration: Entrepreneurship, Sustainability
GMAT 1: 650 Q45 V34 GMAT 2: 740 Q51 V39
GPA: 3.76
WE: Other (Pharmaceuticals and Biotech)

Re: In the figure above, line AC represents a seesaw that is
[#permalink]
Show Tags
25 Jul 2015, 05:33
noTh1ng wrote: What i don't get is why we can assume that the two triangles are similar just because AB = BC?
I mean it looks similar, but why can we apply that? Attachment:
Untitled.png [ 21.95 KiB  Viewed 3602 times ]
You can use three rules to prove that the triangles are similar. 1. AA two angles are equal. 2. SSS All three sides are proportional to each other. 3. SAS One angle is equal and the two adjacent sides are proportional. In this case, you know two angles are equal, x and the 90. Since the height of a point is being measured. Hope it helps.



Manager
Joined: 07 Apr 2015
Posts: 164

Re: In the figure above, line AC represents a seesaw that is
[#permalink]
Show Tags
25 Jul 2015, 06:25
thx akhilbajaj ; good for memorizing this stuff



Senior DS Moderator
Joined: 27 Oct 2017
Posts: 1199
Location: India
Concentration: International Business, General Management
GPA: 3.64
WE: Business Development (Energy and Utilities)

Re: In the figure above, line AC represents a seesaw that is
[#permalink]
Show Tags
05 Jan 2019, 06:08




Re: In the figure above, line AC represents a seesaw that is &nbs
[#permalink]
05 Jan 2019, 06:08






