BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

The lifetime of all the batteries produced by a certain

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Legendary Member
Posts: 2276
Joined: Sat Oct 14, 2017 6:10 am
Followed by:3 members

The lifetime of all the batteries produced by a certain

by VJesus12 » Sun Dec 08, 2019 7:27 am
The lifetime of all the batteries produced by a certain company in a year has a distribution that is symmetric about the mean \(m\). If the distribution has a standard deviation of \(d\), what percent of the distribution is greater than \(m+d?\)

(1) 68 percent of the distribution lies in the interval from \(m-d\) to \(m+d\), inclusive
(2) 16 percent of the distribution is less than \(m-d\)

[spoiler]OA=D[/spoiler]

Source: GMAT Prep
Top
Source: — Data Sufficiency |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3008
Joined: Mon Aug 22, 2016 6:19 am
Location: Grand Central / New York
Thanked: 470 times
Followed by:34 members

by Jay@ManhattanReview » Thu Dec 12, 2019 11:17 pm
VJesus12 wrote:The lifetime of all the batteries produced by a certain company in a year has a distribution that is symmetric about the mean \(m\). If the distribution has a standard deviation of \(d\), what percent of the distribution is greater than \(m+d?\)

(1) 68 percent of the distribution lies in the interval from \(m-d\) to \(m+d\), inclusive
(2) 16 percent of the distribution is less than \(m-d\)

[spoiler]OA=D[/spoiler]

Source: GMAT Prep
Let's take each statement one by one.

(1) 68 percent of the distribution lies in the interval from \(m-d\) to \(m+d\), inclusive.

=> 68/2 = 34 percent of the distribution lies in the interval from 0 to \(m+d\), inclusive.

=> Percent of the distribution is greater than \(m+d\) = 100 - 50 - 34 = 16%. Sufficient.

(2) 16 percent of the distribution is less than \(m-d\).

Since the distribution is symmetric about the mean \(m\), 16 percent of the distribution is greater than \(m+d\). Sufficient.

The correct answer: D

Hope this helps!

-Jay
_________________
Manhattan Review GRE Prep

Locations: GRE Classes Raleigh NC | GRE Prep Course Singapore | GRE Prep Philadelphia | SAT Prep Classes Toronto | and many more...

Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.
Top
Post new topic Post Reply
• Page 1 of 1