 It is currently 24 Nov 2020, 12:24 ### 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

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) of five numbers is 25. After o  Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:
Founder  Joined: 18 Apr 2015
Posts: 13891
GRE 1: Q160 V160 Followers: 313

Kudos [?]: 3676 , given: 12910

The average (arithmetic mean) of five numbers is 25. After o [#permalink]
Expert's post 00:00

Question Stats: 91% (00:46) correct 8% (01:23) wrong based on 35 sessions
The average (arithmetic mean) of five numbers is 25. After one of the numbers is removed, the average (arithmetic mean) of the remaining numbers is 31. What number has been removed?

(A) 1

(B) 6

(C) 11

(D) 24

(E) It cannot be determined from the information given.
[Reveal] Spoiler: OA

_________________
VP Joined: 20 Apr 2016
Posts: 1302
WE: Engineering (Energy and Utilities)
Followers: 22

Kudos [?]: 1340 , given: 251

Re: The average (arithmetic mean) of five numbers is 25. After o [#permalink]
Carcass wrote:
The average (arithmetic mean) of five numbers is 25. After one of the numbers is removed, the average (arithmetic mean) of the remaining numbers is 31. What number has been removed?

(A) 1

(B) 6

(C) 11

(D) 24

(E) It cannot be determined from the information given.

Here,

We know $$Arithmetic mean = \frac{Sum of numbers}{number of terms}$$

i.e. $$\frac{Sum of numbers}{5} = 25$$

or $$Sum of numbers = 125$$

Now if 1 number is removed then Arithmetic mean = 31

i.e. $$\frac{Sum of numbers}{4} = 31$$

or $$Sum of numbers = 124$$

Therefore $$the number removed = 125 - 124 = 1$$
_________________

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

Rules for Posting

Got 20 Kudos? You can get Free GRE Prep Club Tests

GRE Prep Club Members of the Month:TOP 10 members of the month with highest kudos receive access to 3 months GRE Prep Club tests

GRE Instructor Joined: 10 Apr 2015
Posts: 3907
Followers: 163

Kudos [?]: 4766 , given: 70

Re: The average (arithmetic mean) of five numbers is 25. After o [#permalink]
Expert's post
Carcass wrote:
The average (arithmetic mean) of five numbers is 25. After one of the numbers is removed, the average (arithmetic mean) of the remaining numbers is 31. What number has been removed?

(A) 1
(B) 6
(C) 11
(D) 24
(E) It cannot be determined from the information given.

Let the 5 numbers be a, b, c, d, and e

The average (arithmetic mean) of five numbers is 25

We can write: $$\frac{a+b+c+d+e}{5}=25$$

Multiply both sides by 5 to get: $$a+b+c+d+e=125$$

After one of the numbers is removed, the average (arithmetic mean) of the remaining numbers is 31
Let's say we remove the number e

We can now write: $$\frac{a+b+c+d}{4}=31$$

Multiply both sides by 4 to get: $$a+b+c+d=124$$

What number has been removed?
In other words, what is the value of e?

Take:
$$a+b+c+d+e=125$$
$$a+b+c+d=124$$

Subtract the bottom equation from the top equation to get: $$e = 1$$

RELATED VIDEO FROM MY COURSE

_________________

Brent Hanneson – Creator of greenlighttestprep.com  Re: The average (arithmetic mean) of five numbers is 25. After o   [#permalink] 13 Jun 2019, 05:34
Display posts from previous: Sort by

# The average (arithmetic mean) of five numbers is 25. After o  Question banks Downloads My Bookmarks Reviews Important topics  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®.