It is currently 12 Nov 2018, 16:14
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.

The average (arithmetic mean) number of passengers on a

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
1 KUDOS received
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jun 2014
Posts: 4702
GRE 1: Q167 V156
WE: Business Development (Energy and Utilities)
Followers: 90

Kudos [?]: 1596 [1] , given: 373

CAT Tests
The average (arithmetic mean) number of passengers on a [#permalink] New post 24 Nov 2017, 20:47
1
This post received
KUDOS
Expert's post
00:00

Question Stats:

100% (00:29) correct 0% (00:00) wrong based on 2 sessions
The average (arithmetic mean) number of passengers on a subway car is 60. If the number of passengers on a car has a normal distribution with a standard deviation of 20, approximately what percent of subway cars carry more than 80 passengers?

A. 16%
B. 48%
C. 68%
D. 88%
E. 98%

Drill 1
Question: 11
Page: 523
[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

GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jun 2014
Posts: 4702
GRE 1: Q167 V156
WE: Business Development (Energy and Utilities)
Followers: 90

Kudos [?]: 1596 [0], given: 373

CAT Tests
Re: The average (arithmetic mean) number of passengers on a [#permalink] New post 10 Dec 2017, 17:13
Expert's post
Explanation

Adding the standard deviation (20) to the mean (60) gives you the number of passengers in a car that carries exactly one standard deviation above the mean number of passengers (80).

The first standard deviation above the mean represents 34% of the population in a normal distribution, and a further 50% falls below the mean, so 84% of the cars will carry 80 people or fewer. Subtracting this from the entire population (100%) gives you the percent of cars that carry greater than 80: 100% − 84% = 16%.

The answer is choice A.
_________________

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

Try our free Online GRE Test

Re: The average (arithmetic mean) number of passengers on a   [#permalink] 10 Dec 2017, 17:13
Display posts from previous: Sort by

The average (arithmetic mean) number of passengers on a

  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®.