It is currently 22 Sep 2018, 09:26
My Tests

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.

100 tiles are labeled with the integers from 1 to 100 inclus

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jun 2014
Posts: 4459
GRE 1: Q167 V156
WE: Business Development (Energy and Utilities)
Followers: 79

Kudos [?]: 1474 [0], given: 345

CAT Tests
100 tiles are labeled with the integers from 1 to 100 inclus [#permalink] New post 30 Jul 2018, 11:00
Expert's post
00:00

Question Stats:

71% (01:32) correct 28% (01:09) wrong based on 7 sessions
100 tiles are labeled with the integers from 1 to 100 inclusive; no numbers are repeated. If Alma chooses one tile at random, replaces it in the group, and chooses another tile at random, what is the probability that the product of the two integer values on the tiles is odd?

(A) \(\frac{1}{8}\)
(B) \(\frac{1}{4}\)
(C) \(\frac{1}{3}\)
(D) \(\frac{1}{2}\)
(E) \(\frac{3}{4}\)
[Reveal] Spoiler: OA

_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test

Senior Manager
Senior Manager
User avatar
Joined: 07 Jan 2018
Posts: 469
Followers: 4

Kudos [?]: 424 [0], given: 74

CAT Tests
Re: 100 tiles are labeled with the integers from 1 to 100 inclus [#permalink] New post 01 Aug 2018, 09:19
Total number of tiles = 100
Numbering starts with odd and ends with even. i.e from 1 to 100. Therefore there are 50 odd tiles and 50 even tiles.

For product of two number to be odd, both number has to be odd.
Hence number of successful outcome = 50 * 50
Number of possible outcome = 100* 100
Probability = 50*50/100*100 = 1/4

Posted from my mobile device Image
_________________

This is my response to the question and may be incorrect. Feel free to rectify any mistakes

GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jun 2014
Posts: 4459
GRE 1: Q167 V156
WE: Business Development (Energy and Utilities)
Followers: 79

Kudos [?]: 1474 [0], given: 345

CAT Tests
Re: 100 tiles are labeled with the integers from 1 to 100 inclus [#permalink] New post 09 Aug 2018, 14:44
Expert's post
Explanation

Use both probability and number properties concepts in order to answer this question.

First, in order for two integers to produce an odd integer, the two starting integers must be odd. An odd times an odd equals an odd. An even times an odd, by contrast, produces an even, as does an even times an even.

Within the set of tiles, there are 50 even numbers (2, 4, 6, …, 100) and 50 odd numbers (1, 3, 5, …,99).

One randomly-chosen tile will have a \(\frac{50}{100}=\frac{1}{2}\) probability of being even, and a \(\frac{1}{2}\) probability of being odd.

The probability of choosing an odd tile first is \(\frac{1}{2}\) and the probability of choosing an odd tile second is also , so the probability of “first odd and second odd” is \(\frac{1}{2}\times\frac{1}{2}=\frac{1}{4}\).
_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test

GRE Instructor
User avatar
Joined: 10 Apr 2015
Posts: 1056
Followers: 41

Kudos [?]: 935 [0], given: 6

Re: 100 tiles are labeled with the integers from 1 to 100 inclus [#permalink] New post 10 Aug 2018, 05:12
Expert's post
sandy wrote:
100 tiles are labeled with the integers from 1 to 100 inclusive; no numbers are repeated. If Alma chooses one tile at random, replaces it in the group, and chooses another tile at random, what is the probability that the product of the two integer values on the tiles is odd?

(A) \(\frac{1}{8}\)
(B) \(\frac{1}{4}\)
(C) \(\frac{1}{3}\)
(D) \(\frac{1}{2}\)
(E) \(\frac{3}{4}\)


There are 100 tiles. 50 tiles are EVEN and 50 tiles are ODD
The only way to get an ODD product is for the 1st tile to be ODD AND the 2nd tile to be ODD

So, P(product is ODD) = P(1st tile is ODD AND the 2nd tile is ODD)
= P(1st tile is ODD) x P(2nd tile is ODD)
= 50/100 x 50/100
= 1/2 x 1/2
= 1/4

Answer: B

Cheers,
Brent
_________________

Brent Hanneson – Creator of greenlighttestprep.com
Image
Sign up for our free GRE Question of the Day emails

Re: 100 tiles are labeled with the integers from 1 to 100 inclus   [#permalink] 10 Aug 2018, 05:12
Display posts from previous: Sort by

100 tiles are labeled with the integers from 1 to 100 inclus

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

GRE Prep Club Forum Home| About| Terms and Conditions and Privacy Policy| GRE Prep Club Rules| Contact

Powered by phpBB © phpBB Group

Kindly note that the GRE® test is a registered trademark of the Educational Testing Service®, and this site has neither been reviewed nor endorsed by ETS®.