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

It is currently 12 Nov 2018, 23:22

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 November
PrevNext
SuMoTuWeThFrSa
28293031123
45678910
11121314151617
18192021222324
2526272829301
Open Detailed Calendar
  • Essential GMAT Time-Management Hacks

     November 14, 2018

     November 14, 2018

     07:00 PM PST

     08:00 PM PST

    Join the webinar and learn time-management tactics that will guarantee you answer all questions, in all sections, on time. Save your spot today! Nov. 14th at 7 PM PST
  • $450 Tuition Credit & Official CAT Packs FREE

     November 15, 2018

     November 15, 2018

     10:00 PM MST

     11:00 PM MST

    EMPOWERgmat is giving away the complete Official GMAT Exam Pack collection worth $100 with the 3 Month Pack ($299)

A certain airport security scanner designed to detect explosives in lu

  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: 50545
A certain airport security scanner designed to detect explosives in lu  [#permalink]

Show Tags

New post 03 Jul 2018, 10:15
00:00
A
B
C
D
E

Difficulty:

  75% (hard)

Question Stats:

46% (01:41) correct 54% (01:53) wrong based on 111 sessions

HideShow timer Statistics

A certain airport security scanner designed to detect explosives in luggage will alert the scanner’s operator whenever the piece of luggage passing under the scanner contains an explosive. The scanner will erroneously alert the operator for only one percent of the pieces of luggage that contain no explosives. Thus in ninety‑nine out of a hundred alerts explosives will actually be present.

The reasoning in the argument is flawed because the argument


(A) ignores the possibility of the scanner’s failing to signal an alert when the luggage does contain an explosive

(B) draws a general conclusion about reliability on the basis of a sample that is likely to be biased

(C) ignores the possibility of human error on the part of the scanner’s operator once the scanner has alerted him or her

(D) fails to acknowledge the possibility that the scanner will not be equally sensitive to all kinds of explosives

(E) substitutes one group for a different group in the statement of a percentage

_________________

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: 14 Oct 2017
Posts: 10
CAT Tests
Re: A certain airport security scanner designed to detect explosives in lu  [#permalink]

Show Tags

New post 03 Jul 2018, 10:29
Answer is E? Incorrectly comparing no. Of erroneous alerts with no. Of pieces of luggage with no explosives


Sent from my iPhone using GMAT Club Forum mobile app
Board of Directors
User avatar
P
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 4209
Location: India
GPA: 3.5
WE: Business Development (Commercial Banking)
GMAT ToolKit User Premium Member
Re: A certain airport security scanner designed to detect explosives in lu  [#permalink]

Show Tags

New post 03 Jul 2018, 10:43
gilltaurus wrote:
Answer is E? Incorrectly comparing no. Of erroneous alerts with no. Of pieces of luggage with no explosives


Sent from my iPhone using GMAT Club Forum mobile app


With the same opinion, must be (E)

Quote:
A certain airport security scanner designed to detect explosives in luggage will alert the scanner’s operator whenever the piece of luggage passing under the scanner contains an explosive. The scanner will erroneously alert the operator for only one percent of the pieces of luggage that contain no explosives. Thus in ninety‑nine out of a hundred alerts explosives will actually be present.


Compares percentage error in one statement to the actual number of alerts !!
_________________

Thanks and Regards

Abhishek....

PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS

How to use Search Function in GMAT Club | Rules for Posting in QA forum | Writing Mathematical Formulas |Rules for Posting in VA forum | Request Expert's Reply ( VA Forum Only )

Senior Manager
Senior Manager
User avatar
P
Joined: 07 Dec 2017
Posts: 289
Re: A certain airport security scanner designed to detect explosives in lu  [#permalink]

Show Tags

New post 10 Jul 2018, 17:59
IMO ANSWER E:

This is how: acc to the premise, the scanner will show 1% of false positive for all non-explosive luggage

Let's take nos: 100 non-explosive pieces of luggage, the scanner will result in 1 case of False positive but based
on this information, we cant deduce the accuracy for all the luggage which contain explosives as we have
info available for the accuracy of false + for non-explosive Luggage
GMAT Club Bot
Re: A certain airport security scanner designed to detect explosives in lu &nbs [#permalink] 10 Jul 2018, 17:59
Display posts from previous: Sort by

A certain airport security scanner designed to detect explosives in lu

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


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®.