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 2007:30 AM PST
-08:30 AM PST
Learn what truly sets the UC Riverside MBA apart and how it helps in your professional growth
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 Aug 2023, 05:00
Kudos
Bookmarks
A
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
65%
(hard)
Question Stats:
59% (01:36) correct
41%
(02:07)
wrong
based on 1067
sessions
History
Date
Time
Result
Not Attempted Yet
Each of the 20 people working in a certain office contributed either $9, $10, or $11 toward an office party. What was the average (arithmetic mean) amount contributed per person in the office?
(1) The number of people who contributed $9 was the same as the number of people who contributed $11.
(2) The number of people who contributed $9 was more than the number of people who contributed $10.
(1) The number of people who contributed $9 was the same as the number of people who contributed $11.
(2) The number of people who contributed $9 was more than the number of people who contributed $10.
03 Sep 2023, 16:41
Kudos
Bookmarks
Bunuel
n = a + b + c = 20
We need to answer the question:
average = (9a + 10b + 11c)/(20) = ?
Statement One Alone:
=> The number of people who contributed $9 was the same as the number of people who contributed $11.
a = c
a + b + a = 20
b = 20 – 2a
average = (9a + 10(20 – 2a) + 11a)/20 = 200/20 = $10
Statement one is sufficient. Eliminate answer choices B, C, and E.
Statement Two Alone:
=> The number of people who contributed $9 was more than the number of people who contributed $10.
If each person contributed $9, then the average was $9.
Whereas, if 19 people contributed $9 and 1 person contributed $10, then the average is greater than $9.
Statement two is not sufficient.
Answer: A
03 Aug 2023, 05:15
Kudos
Bookmarks
Bunuel
In a set, the positive difference w.r.t to the average (arithmetic mean) compensates for the negative difference w.r.t average (arithmetic mean).
Statement 1
(1) The number of people who contributed $9 was the same as the number of people who contributed $11.
- Each person who contributed $9 contributed $1 less than $10.
- Each person who contributed $11 contributed $1 more than $10.
We know that the number of people in the above two categories was the same. Hence, for each person who contributed $9, another person contributed $11, thereby keeping the average at $10. The statement is sufficient and we can eliminate B, C, and E.
Statement 2
(2) The number of people who contributed $9 was more than the number of people who contributed $10.
Knowing the fact that the number of people who contributed $9 was more than the number of people who contributed $10 doesn't help us find the average.
For example, if the number of people who contributed $11 was the same as the number of people who contributed $9, the average was $10. However, if the number of people between the two categories (people who contributed $9 and people who contributed $11) was not the same, the average was not $10.
Hence, the statement alone is not sufficient. We can eliminate D.
Option A
