Events & Promotions
|
|
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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Nov 1811:00 AM PST
-12:00 PM PST
Join us in a live GMAT practice session and solve 30 challenging GMAT questions with other test takers in timed conditions, covering GMAT Quant, Data Sufficiency, Data Insights, Reading Comprehension, and Critical Reasoning questions.
Nov 2211:00 AM IST
-01:00 PM IST
Do RC/MSR passages scare you? e-GMAT is conducting a masterclass to help you learn – Learn effective reading strategies Tackle difficult RC & MSR with confidence Excel in timed test environment- Nov 23
11:00 AM IST
-01:00 PM IST
Attend this free GMAT Algebra Webinar and learn how to master the most challenging Inequalities and Absolute Value problems with ease. 
Nov 2510:00 AM EST
-11:00 AM EST
Prefer video-based learning? The Target Test Prep OnDemand course is a one-of-a-kind video masterclass featuring 400 hours of lecture-style teaching by Scott Woodbury-Stewart, founder of Target Test Prep and one of the most accomplished GMAT instructors.
03 Jul 2024, 01:30
Kudos
Bookmarks
C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
85%
(hard)
Question Stats:
44% (02:16) correct
56%
(02:07)
wrong
based on 142
sessions
History
Date
Time
Result
Not Attempted Yet
Felipe stores his contacts’ telephone numbers in two places: in the memory of his cell phone, and in a notebook. If some numbers are stored both in his cell phone memory and in his notebook, does his notebook contain a greater number of telephone numbers than does his cell phone memory?
(1) \(\frac{2}{3}\) of all the distinct telephone numbers Felipe has recorded are recorded in his notebook.
(2) \(\frac{4}{7}\) of the telephone numbers stored in Felipe’s cell phone memory are also recorded in his notebook.
(1) \(\frac{2}{3}\) of all the distinct telephone numbers Felipe has recorded are recorded in his notebook.
(2) \(\frac{4}{7}\) of the telephone numbers stored in Felipe’s cell phone memory are also recorded in his notebook.
Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Data Sufficiency (DS) Forum
Still interested in this question? Check out the "Best Topics" block below for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
03 Jul 2024, 04:19
Kudos
Bookmarks
Given - Felipe stores his contacts’ telephone numbers in two places: in the memory of his cell phone, and in a notebook. If some numbers are stored both in his cell phone memory and in his notebook.
To find - does his notebook contain a greater number of telephone numbers than does his cell phone memory?
A=Cell phone, B = Notebook, Is n(B) > n(A) ?
n(A) = total number of contacts in cellphone,
n(B) = total number of contacts in notebook,
n(A∩B) = total number of contacts in both
n(AUB) = n(A) + n(B) - n(A∩B)
1st - 2/3 of all the distinct telephone numbers Felipe has recorded are recorded in his notebook.
A distinct = n(A) - n(A∩B), B distinct = n(B) - n(A∩B) Total distinct = n(A) + n(B) - 2*n(A∩B)
n(B) - n(A∩B) = 2*((n(A) + n(B) - 2*n(A∩B))/3
3n(B) - 3n(A∩B) = 2n(A) + 2n(B) -4n(A∩B)
n(B) = 2n(A) - n(A∩B)
n(B) = n(A) + n(A) - n(A∩B)
This shows n(B) > n(A) (As n(A) - n(A∩B) is all the distinct telephone numbers Felipe has recorded are recorded in his cell phone)
Sufficient.
2nd - 4/7 of the telephone numbers stored in Felipe’s cell phone memory are also recorded in his notebook.
Assuming total of telephone numbers n(AUB) = 7k, n(A∩B) = 4k,
n(A) + n(B) = n(AUB) + n(A∩B) = 11k
But nothing mentioned about distribution in between cell phone and notebook so we cant conclude anything. Not sufficient
Answer A.
To find - does his notebook contain a greater number of telephone numbers than does his cell phone memory?
A=Cell phone, B = Notebook, Is n(B) > n(A) ?
n(A) = total number of contacts in cellphone,
n(B) = total number of contacts in notebook,
n(A∩B) = total number of contacts in both
n(AUB) = n(A) + n(B) - n(A∩B)
1st - 2/3 of all the distinct telephone numbers Felipe has recorded are recorded in his notebook.
A distinct = n(A) - n(A∩B), B distinct = n(B) - n(A∩B) Total distinct = n(A) + n(B) - 2*n(A∩B)
n(B) - n(A∩B) = 2*((n(A) + n(B) - 2*n(A∩B))/3
3n(B) - 3n(A∩B) = 2n(A) + 2n(B) -4n(A∩B)
n(B) = 2n(A) - n(A∩B)
n(B) = n(A) + n(A) - n(A∩B)
This shows n(B) > n(A) (As n(A) - n(A∩B) is all the distinct telephone numbers Felipe has recorded are recorded in his cell phone)
Sufficient.
2nd - 4/7 of the telephone numbers stored in Felipe’s cell phone memory are also recorded in his notebook.
Assuming total of telephone numbers n(AUB) = 7k, n(A∩B) = 4k,
n(A) + n(B) = n(AUB) + n(A∩B) = 11k
But nothing mentioned about distribution in between cell phone and notebook so we cant conclude anything. Not sufficient
Answer A.
03 Jul 2024, 04:43
Kudos
Bookmarks
All numbers = Distinct in Memory + Distinct in Notebook + Common in Memory & Notebook
Numbers in Memory = Distinct in Memory + Common in Memory & Notebook
Numbers in Notebook = Distinct in Notebook + Common in Memory & Notebook
Question: Numbers in Notebook > Numbers in Memory
Distinct in Notebook > Distinct in Memory ?
Statement 1: \(\frac{2}{3}\) of all the distinct telephone numbers Felipe has recorded are recorded in his notebook
Distinct Numbers = Distinct in Memory + Distinct in Notebook = \(\frac{x}{3}+\frac{2x}{3}\)
Distinct in Notebook > Distinct in Memory
Sufficient
Statement 2: \(\frac{4}{7}\) of the telephone numbers stored in Felipe’s cell phone memory are also recorded in his notebook.
No info about numbers in notebook alone.
Not Sufficient
Hence, Answer is A
Numbers in Memory = Distinct in Memory + Common in Memory & Notebook
Numbers in Notebook = Distinct in Notebook + Common in Memory & Notebook
Question: Numbers in Notebook > Numbers in Memory
Distinct in Notebook > Distinct in Memory ?
Statement 1: \(\frac{2}{3}\) of all the distinct telephone numbers Felipe has recorded are recorded in his notebook
Distinct Numbers = Distinct in Memory + Distinct in Notebook = \(\frac{x}{3}+\frac{2x}{3}\)
Distinct in Notebook > Distinct in Memory
Sufficient
Statement 2: \(\frac{4}{7}\) of the telephone numbers stored in Felipe’s cell phone memory are also recorded in his notebook.
No info about numbers in notebook alone.
Not Sufficient
Hence, Answer is A
