It is currently 16 Dec 2017, 07:16

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

Events & Promotions in June
Open Detailed Calendar

If positive integer n<=3 and n is the number of times a coin is flippe

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

Hide Tags

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 42628

Kudos [?]: 135818 [0], given: 12715

If positive integer n<=3 and n is the number of times a coin is flippe [#permalink]

Show Tags

New post 11 Oct 2016, 01:15
Expert's post
3
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  95% (hard)

Question Stats:

37% (01:41) correct 63% (01:26) wrong based on 94 sessions

HideShow timer Statistics

If positive integer n<=3 and n is the number of times a coin is flipped, what is the value of n?

(1) The probability of getting heads exactly once is 1/2

(2) The probability of getting at least one tail is greater than 1/2
[Reveal] Spoiler: OA

_________________

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

Kudos [?]: 135818 [0], given: 12715

Board of Directors
User avatar
D
Status: Aiming MBA
Joined: 18 Jul 2015
Posts: 2879

Kudos [?]: 974 [0], given: 71

Location: India
Concentration: Healthcare, Technology
GPA: 3.65
WE: Information Technology (Health Care)
Premium Member Reviews Badge
Re: If positive integer n<=3 and n is the number of times a coin is flippe [#permalink]

Show Tags

New post 11 Oct 2016, 06:18
Bunuel wrote:
If positive integer n<=3 and n is the number of times a coin is flipped, what is the value of n?

(1) The probability of getting heads exactly once is 1/2

(2) The probability of getting at least one tail is greater than 1/2


IMO answer should be C.

We know that n <=3 => n =1,2 or 3

Statement 1 : P(Exactly once Head) = 1/2

if n = 1, then also the condition is satisfied.
if n = 2, we can have HT,TH,HH,TT. So, exactly once head is two times out of the four. hence, here also, we have probability of exactly once head = 1/2. Hence, insufficient.
For, n =3, we will get exactly one head for 3 cases out of 8, this scenario won't work.

Statement 2 : P(At least one tail) > 1/2.

For n=1,P( at least one tail) = 1/2. hence, this scenario will be invalid.

For n=2 and n=3, we will get a valid scenario. Hence, two values of n. Insufficient.

Combing, only value of n that will work is n=2. Hence, Sufficient.
_________________

How I improved from V21 to V40! ?

Kudos [?]: 974 [0], given: 71

VP
VP
avatar
S
Joined: 12 Dec 2016
Posts: 1366

Kudos [?]: 51 [0], given: 1452

Location: United States
GMAT 1: 700 Q49 V33
GPA: 3.64
GMAT ToolKit User Premium Member
Re: If positive integer n<=3 and n is the number of times a coin is flippe [#permalink]

Show Tags

New post 29 Aug 2017, 00:44
st1 tells that n can be either 1 or 2
st2 indicates that n can be 2 or 3.

=> C

Kudos [?]: 51 [0], given: 1452

Re: If positive integer n<=3 and n is the number of times a coin is flippe   [#permalink] 29 Aug 2017, 00:44
Display posts from previous: Sort by

If positive integer n<=3 and n is the number of times a coin is flippe

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


GMAT Club MBA Forum Home| About| Terms and Conditions| 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®.