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

It is currently 17 Dec 2018, 09:02

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 December
PrevNext
SuMoTuWeThFrSa
2526272829301
2345678
9101112131415
16171819202122
23242526272829
303112345
Open Detailed Calendar
  • 10 Keys to nail DS and CR questions

     December 17, 2018

     December 17, 2018

     06:00 PM PST

     07:00 PM PST

    Join our live webinar and learn how to approach Data Sufficiency and Critical Reasoning problems, how to identify the best way to solve each question and what most people do wrong.
  • R1 Admission Decisions: Estimated Decision Timelines and Chat Links for Major BSchools

     December 17, 2018

     December 17, 2018

     10:00 PM PST

     11:00 PM PST

    From Dec 5th onward, American programs will start releasing R1 decisions. Chat Rooms: We have also assigned chat rooms for every school so that applicants can stay in touch and exchange information/update during decision period.

The probability that a convenience store has cans of iced

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

Hide Tags

Intern
Intern
User avatar
Joined: 20 Feb 2012
Posts: 30
The probability that a convenience store has cans of iced  [#permalink]

Show Tags

New post 06 Mar 2012, 12:26
1
3
1. The probability that a convenience store has cans of iced tea in stock is 50%. If James stops by 3 convenience stores on his way to work, what is the probability that he will be able to buy a can of iced tea?

2. The probability that a convenience store has no iced tea is 50%. If James stops by 3 convenience stores on his way to work, what is the probability that at least one of the stores will not have a can of iced tea?

3. The probability that a convenience store has cans of iced tea in stock is 50%. If James stops by 3 convenience stores on his way to work, what is the probability that he will not be able to buy a can of iced tea?
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 51263
Re: probability  [#permalink]

Show Tags

New post 06 Mar 2012, 12:44
2
2
1. The probability that a convenience store has cans of iced tea in stock is 50%. If James stops by 3 convenience stores on his way to work, what is the probability that he will be able to buy a can of iced tea?

James will be able to buy a can of iced tea if at least one of the shops has it and the probability that at least one of the shops has an iced tea is P=1-(none of the shops has an iced tea)=1-P(NNN)=1-1/2^3=7/8.

2. The probability that a convenience store has no iced tea is 50%. If James stops by 3 convenience stores on his way to work, what is the probability that at least one of the stores will not have a can of iced tea?

The probability that at least one of the stores will not have a can of iced tea is 1-(all shops have an iced tea)=1-P(YYY)=1-1/2^2=7/8. Notice that we have the same answer as above. That's because the probability distribution is symmetrical for this question thus the probability that at least one of the stores will NOT have a can of iced tea = the probability that at least one of the stores will have a can of iced tea

3. The probability that a convenience store has cans of iced tea in stock is 50%. If James stops by 3 convenience stores on his way to work, what is the probability that he will not be able to buy a can of iced tea?

James won't be able to buy a can of iced tea if none of the shops has it: P(NNN)=1/2^3=1/8.

Hope it's clear.
_________________

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

Current Student
User avatar
B
Joined: 12 Oct 2012
Posts: 113
WE: General Management (Other)
GMAT ToolKit User
Re: probability  [#permalink]

Show Tags

New post 17 Nov 2012, 00:13
Bunuel wrote:
1. The probability that a convenience store has cans of iced tea in stock is 50%. If James stops by 3 convenience stores on his way to work, what is the probability that he will be able to buy a can of iced tea?

James will be able to buy a can of iced tea if at least one of the shops has it and the probability that at least one of the shops has an iced tea is P=1-(none of the shops has an iced tea)=1-P(NNN)=1-1/2^3=7/8.

2. The probability that a convenience store has no iced tea is 50%. If James stops by 3 convenience stores on his way to work, what is the probability that at least one of the stores will not have a can of iced tea?

The probability that at least one of the stores will not have a can of iced tea is 1-(all shops have an iced tea)=1-P(YYY)=1-1/2^2=7/8. Notice that we have the same answer as above. That's because the probability distribution is symmetrical for this question thus the probability that at least one of the stores will NOT have a can of iced tea = the probability that at least one of the stores will have a can of iced tea

3. The probability that a convenience store has cans of iced tea in stock is 50%. If James stops by 3 convenience stores on his way to work, what is the probability that he will not be able to buy a can of iced tea?

James won't be able to buy a can of iced tea if none of the shops has it: P(NNN)=1/2^3=1/8.

Hope it's clear.



Hi Bunuel,

WRT Q2.


P(atleast one does not have)= P(one does not have) + P( two don't have) + P(all 3 don't have)

= P(one does not have)*P(2 have) +
P (2 don't have)*P(one has) +
P(all 3 don't have)
= 1/2*1/2*1/2 + 1/4*1/2 + 1/8
= 3/8

Why is it giving me a wrong answer?I know I am missing something.

Can someone please explain?

Infact Is my methos wrong, coz i am trying to solve Qs by this method. I understood the 1-p methos as well.
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 51263
Re: probability  [#permalink]

Show Tags

New post 17 Nov 2012, 05:53
1
aditi2013 wrote:
Bunuel wrote:
1. The probability that a convenience store has cans of iced tea in stock is 50%. If James stops by 3 convenience stores on his way to work, what is the probability that he will be able to buy a can of iced tea?

James will be able to buy a can of iced tea if at least one of the shops has it and the probability that at least one of the shops has an iced tea is P=1-(none of the shops has an iced tea)=1-P(NNN)=1-1/2^3=7/8.

2. The probability that a convenience store has no iced tea is 50%. If James stops by 3 convenience stores on his way to work, what is the probability that at least one of the stores will not have a can of iced tea?

The probability that at least one of the stores will not have a can of iced tea is 1-(all shops have an iced tea)=1-P(YYY)=1-1/2^2=7/8. Notice that we have the same answer as above. That's because the probability distribution is symmetrical for this question thus the probability that at least one of the stores will NOT have a can of iced tea = the probability that at least one of the stores will have a can of iced tea

3. The probability that a convenience store has cans of iced tea in stock is 50%. If James stops by 3 convenience stores on his way to work, what is the probability that he will not be able to buy a can of iced tea?

James won't be able to buy a can of iced tea if none of the shops has it: P(NNN)=1/2^3=1/8.

Hope it's clear.



Hi Bunuel,

WRT Q2.


P(atleast one does not have)= P(one does not have) + P( two don't have) + P(all 3 don't have)

= P(one does not have)*P(2 have) +
P (2 don't have)*P(one has) +
P(all 3 don't have)
= 1/2*1/2*1/2 + 1/4*1/2 + 1/8
= 3/8

Why is it giving me a wrong answer?I know I am missing something.

Can someone please explain?

Infact Is my methos wrong, coz i am trying to solve Qs by this method. I understood the 1-p methos as well.


Direct probability approach:
One store does not have an iced tea: P(YYN)=3*1/2*1/2^2=3/8 (multiplying by 3 as scenario YYN can occur in 3!/2!=3 ways: YYN, YNY, NYY);
Two shops does not have an iced tea: P(YNN)=3*1/2^2*1/2=3/8 (multiplying by 3 as scenario YNN can occur in 3!/2!=3 ways: YNN, NYN, NNY);
All three shops does not have an iced tea: P(NNN)=1/2^3=1/8;

P=3/8+3/8+1/8=7/8.

Hope it's clear.
_________________

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

Current Student
User avatar
B
Joined: 12 Oct 2012
Posts: 113
WE: General Management (Other)
GMAT ToolKit User
Re: probability  [#permalink]

Show Tags

New post 17 Nov 2012, 07:05
Bunuel wrote:
aditi2013 wrote:
Bunuel wrote:
1. The probability that a convenience store has cans of iced tea in stock is 50%. If James stops by 3 convenience stores on his way to work, what is the probability that he will be able to buy a can of iced tea?

James will be able to buy a can of iced tea if at least one of the shops has it and the probability that at least one of the shops has an iced tea is P=1-(none of the shops has an iced tea)=1-P(NNN)=1-1/2^3=7/8.

2. The probability that a convenience store has no iced tea is 50%. If James stops by 3 convenience stores on his way to work, what is the probability that at least one of the stores will not have a can of iced tea?

The probability that at least one of the stores will not have a can of iced tea is 1-(all shops have an iced tea)=1-P(YYY)=1-1/2^2=7/8. Notice that we have the same answer as above. That's because the probability distribution is symmetrical for this question thus the probability that at least one of the stores will NOT have a can of iced tea = the probability that at least one of the stores will have a can of iced tea

3. The probability that a convenience store has cans of iced tea in stock is 50%. If James stops by 3 convenience stores on his way to work, what is the probability that he will not be able to buy a can of iced tea?

James won't be able to buy a can of iced tea if none of the shops has it: P(NNN)=1/2^3=1/8.

Hope it's clear.



Hi Bunuel,

WRT Q2.


P(atleast one does not have)= P(one does not have) + P( two don't have) + P(all 3 don't have)

= P(one does not have)*P(2 have) +
P (2 don't have)*P(one has) +
P(all 3 don't have)
= 1/2*1/2*1/2 + 1/4*1/2 + 1/8
= 3/8

Why is it giving me a wrong answer?I know I am missing something.

Can someone please explain?

Infact Is my methos wrong, coz i am trying to solve Qs by this method. I understood the 1-p methos as well.


Direct probability approach:
One store does not have an iced tea: P(YYN)=3*1/2*1/2^2=3/8 (multiplying by 3 as scenario YYN can occur in 3!/2!=3 ways: YYN, YNY, NYY);
Two shops does not have an iced tea: P(YNN)=3*1/2^2*1/2=3/8 (multiplying by 3 as scenario YNN can occur in 3!/2!=3 ways: YNN, NYN, NNY);
All three shops does not have an iced tea: P(NNN)=1/2^3=1/8;

P=3/8+3/8+1/8=7/8.

Hope it's clear.


Thanks Bunuel. I am really glad that I am a GC member.

Just one last Question, how do we come to know that we have to take the scenarios of possible positions of the outcomes (like yyn, yny, nyy)??
I often miss on that. Also is there a general rule which applies here to take the positions into account.
I have read all theory but guess challenges come only when u start solving. Pls help.
Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 9198
Premium Member
Re: The probability that a convenience store has cans of iced  [#permalink]

Show Tags

New post 20 Feb 2018, 01:04
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

GMAT Club Bot
Re: The probability that a convenience store has cans of iced &nbs [#permalink] 20 Feb 2018, 01:04
Display posts from previous: Sort by

The probability that a convenience store has cans of iced

  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®.