GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 16 Jan 2019, 16:39

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel
Events & Promotions in January
PrevNext
SuMoTuWeThFrSa
303112345
6789101112
13141516171819
20212223242526
272829303112
Open Detailed Calendar
  • The winning strategy for a high GRE score

     January 17, 2019

     January 17, 2019

     08:00 AM PST

     09:00 AM PST

    Learn the winning strategy for a high GRE score — what do people who reach a high score do differently? We're going to share insights, tips and strategies from data we've collected from over 50,000 students who used examPAL.
  • Free GMAT Strategy Webinar

     January 19, 2019

     January 19, 2019

     07:00 AM PST

     09:00 AM PST

    Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.

M70-24

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 52161
M70-24  [#permalink]

Show Tags

New post 03 Sep 2018, 04:51
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

50% (01:22) correct 50% (00:35) wrong based on 6 sessions

HideShow timer Statistics

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 52161
Re M70-24  [#permalink]

Show Tags

New post 03 Sep 2018, 04:52
Official Solution:


We’ll go for ALTERNATIVE since we can play with the figure to eliminate the wrong answers.

(1) ∠ECD is an inscribed angle facing a diameter, meaning that it equals 90°, but moving point D closer to or farther from point C shows us that the size of ∠ACD can change – not enough! (A) and (D) are eliminated.

(2) The two equal angles mean that the triangle is an isosceles. This means that, due to symmetry, ∠ACD = ∠BCE − but that’s not enough in order to determine their size. (B) is eliminated.

If we combine the two statements, ∠ACD + ∠BCE = 90˚, and since they are both equal, each of them is 45˚ − that’s enough! (E) is eliminated.


Answer: C
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Intern
Intern
avatar
B
Joined: 10 May 2018
Posts: 13
Location: Argentina
Schools: INSEAD Jan '20
GMAT 1: 680 Q48 V35
Re: M70-24  [#permalink]

Show Tags

New post 13 Sep 2018, 17:20
Bunuel wrote:
Official Solution:


(1) ∠ECD is an inscribed angle facing a diameter, meaning that it equals 90°, but moving point D closer to or farther from point C shows us that the size of ∠ACD can change – not enough! (A) and (D) are eliminated.


Answer: C


Hi Bunuel,

What do you mean by moving point D closer to or farther from point C? if DE is the diameter and C is in the tangent shoulnd't both angles be the same? I mean, doesn't statement 1 give enough evidence to conclude what statement 2 says?

thanks!
Senior Manager
Senior Manager
User avatar
S
Joined: 07 Oct 2017
Posts: 260
Re: M70-24  [#permalink]

Show Tags

New post 13 Sep 2018, 21:43
tsuxinhah wrote:
Bunuel wrote:
Official Solution:


(1) ∠ECD is an inscribed angle facing a diameter, meaning that it equals 90°, but moving point D closer to or farther from point C shows us that the size of ∠ACD can change – not enough! (A) and (D) are eliminated.


Answer: C


Hi Bunuel,

What do you mean by moving point D closer to or farther from point C? if DE is the diameter and C is in the tangent shoulnd't both angles be the same? I mean, doesn't statement 1 give enough evidence to conclude what statement 2 says?

thanks!
Hi tsuxinhah

For Geometry DS, always try to imagine if we can restrict the figure in one orientation. For statement 1, diameter is restricted but point C can lie on any point in the circumference as it is not restricted by the given condition.

This will in turn keep changing the desired angle and hence statement is not sufficient.

Thank you = Kudos
_________________

Thank you =Kudos
The best thing in life lies on the other side of the pain.

Intern
Intern
avatar
B
Joined: 16 Sep 2018
Posts: 5
Re: M70-24  [#permalink]

Show Tags

New post 30 Sep 2018, 22:03
Answer C is only correct if we know that AB is parallel to DE. But we dont know that for sure so answer E.
Or can someone pls tell me if a made a mistake?

Posted from my mobile device
Director
Director
User avatar
P
Joined: 08 Jun 2013
Posts: 538
Location: France
Schools: INSEAD Jan '19
GMAT 1: 200 Q1 V1
GPA: 3.82
WE: Consulting (Other)
GMAT ToolKit User Premium Member
Re: M70-24  [#permalink]

Show Tags

New post 01 Oct 2018, 00:31
Phibo wrote:
Answer C is only correct if we know that AB is parallel to DE. But we dont know that for sure so answer E.
Or can someone pls tell me if a made a mistake?

Posted from my mobile device


St : 1 DE is diameter

St 2 : Angle CDE and CED are equal.

Now Point C is on circle.

So angle C is 90 degrees.

Angle CDE and Angle CED = 45 degrees.

So DE parallel to line ACB.

Does this help?
_________________

Everything will fall into place…

There is perfect timing for
everything and everyone.
Never doubt, But Work on
improving yourself,
Keep the faith and
Stay ready. When it’s
finally your turn,
It will all make sense.

Intern
Intern
avatar
B
Joined: 16 Sep 2018
Posts: 5
Re: M70-24  [#permalink]

Show Tags

New post 01 Oct 2018, 00:51
Thanks for your quick reply. Sry I totally missed the fact that C has to be the tanget point of AB. Otherwise the test cant ask for the ACD-angle.
thx again

Posted from my mobile device
GMAT Club Bot
Re: M70-24 &nbs [#permalink] 01 Oct 2018, 00:51
Display posts from previous: Sort by

M70-24

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  

Moderators: chetan2u, Bunuel



Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.