Forum Home > GMAT > Quantitative > Problem Solving (PS)
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.
Dec 1511:00 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.
Dec 1608:00 AM PST
-11:59 PM PST
GMAT Club 12 Days of Christmas is a 4th Annual GMAT Club Winter Competition based on solving questions. This is the Winter GMAT competition on GMAT Club with an amazing opportunity to win over $40,000 worth of prizes!- Dec 17
09:00 AM PST
-10:00 AM PST
Join Manhattan Prep instructor Whitney Garner for a fun—and thorough—review of logic-based (non-math) problems, with a particular emphasis on Data Sufficiency and Two-Parts. - Dec 18
10:00 AM PST
-11:00 AM PST
Here is the essential guide to securing scholarships as an MBA student! In this video, we explore the various types of scholarships available, including need-based and merit-based options.
22 Aug 2019, 00:04
Kudos
Bookmarks
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
5%
(low)
Question Stats:
93% (01:33) correct
7%
(03:10)
wrong
based on 54
sessions
History
Date
Time
Result
Not Attempted Yet
The average (arithmetic mean) of a set of n numbers is 75. If adding the number 160 in the set raises the average to 80, what is the value of n?
A. 20
B. 16
C. 8
D. 6
E. 4
A. 20
B. 16
C. 8
D. 6
E. 4
22 Aug 2019, 00:16
Kudos
Bookmarks
The sum of a set of \(n\) numbers is \(75n\).
75n + 160 = 80(n+1)
--> 80 = 5n
--> n = 16
Answer is (B)
Posted from my mobile device
75n + 160 = 80(n+1)
--> 80 = 5n
--> n = 16
Answer is (B)
Posted from my mobile device
23 Mar 2020, 08:14
Kudos
Bookmarks
Bunuel
The average (arithmetic mean) of a set of n numbers is 75. If adding the number 160 in the set raises the average to 80, what is the value of n?
A. 20
B. 16
C. 8
D. 6
E. 4
A. 20
B. 16
C. 8
D. 6
E. 4
The average (arithmetic mean) of a set of n numbers is 75.
We can write: (sum of all n numbers)/n = 75
Multiply both sides of the equation by n to get: sum of all n numbers = 75n
Adding the number 160 in the set raises the average to 80
Since we've added ONE number, we now have n + 1 numbers
And the SUM of these n+1 numbers = (sum of the original n numbers) + 160
In other words, the SUM of these n+1 numbers = 75n + 160
If the new average of the n+1 number is 80, we can write: (75n + 160)/(n + 1) = 80
What is the value of n?
Take: (75n + 160)/(n + 1) = 80
Multiply both sides by (n + 1) to get: 75n + 160 = 80(n + 1)
Expand: 75n + 160 = 80n + 80
Subtract 80 from both sides: 75n + 80 = 80n
Subtract 75n from both sides: 80 = 5n
Divide both sides by 5 to get: 16 = n
Answer: B
RELATED VIDEO
