Last visit was: 23 Nov 2024, 01:11 It is currently 23 Nov 2024, 01:11

Close

GRE Prep 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 GRE 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.

Close

Request Expert Reply

Confirm Cancel
avatar
Intern
Intern
Joined: 08 Sep 2016
Posts: 6
Own Kudos [?]: 12 [10]
Given Kudos: 0
Send PM
Verbal Expert
Joined: 18 Apr 2015
Posts: 30006
Own Kudos [?]: 36356 [0]
Given Kudos: 25927
Send PM
User avatar
Retired Moderator
Joined: 07 Jun 2014
Posts: 4813
Own Kudos [?]: 11194 [4]
Given Kudos: 0
GRE 1: Q167 V156
WE:Business Development (Energy and Utilities)
Send PM
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Own Kudos [?]: 12196 [3]
Given Kudos: 136
Send PM
Re: A set of 7 integers has a range of 2, an average of 3, and a [#permalink]
2
1
Bookmarks
Sakshi7591 wrote:
A set of 7 integers has a range of 2, an average of 3, and a mode of 3.


Quantity A
Quantity B
The third number in the set when the numbers
are arranged in ascending order
The fifth number in the set when the numbers
are arranged in ascending order


A)The quantity in Column A is greater.
B)The quantity in Column B is greater.
C)The two quantities are equal.
D)The relationship cannot be determined from the information given.


A student asked me to elaborate on this question, so here goes....

Since the numbers in the set are INTEGERS, and since the range = 2, we can conclude that some integers in the set will be repeated. I say this because we can't have a range of 2 with 7 DIFFERENT integers.

Also, the fact that the mode is 3 means that 3 is repeated the MOST TIMES.

Since the MEAN = 3, then the repeated 3's must appear in the middle of the set.
To show why this is, let's look at a situation in which the repeated 3's do NOT appear in the middle of the set.
For example, let's say that the 3's are the SMALLEST values in the set.
This is no good, since some of the other numbers would have to be greater than 3.
So, we'd have a set that looks something like {3, 3, 3, 3+, 3+, 3+, 3+}, where 3+ represents a number greater than 3.
This set will have a mean that's greater than 3. I know this because the set {3, 3, 3, 3, 3, 3, 3} has a mean of 3. So, if we replace one or more 3 with 3+, the mean must be greater than 3.
Given this, the 3's cannot be the SMALLEST values.
Using similar logic, we can conclude that the 3's cannot be the GREATEST values.

So, the 3's must be the MIDDLEMOST values.
This means 2 must be the smallest value and 4 must be the greatest value.
So, we have something like {2, some 3's, 4}

So, one option might be {2, 3, 3, 3, 3, 3, 4}
This set meet all of the given conditions.

Of course, we could also have {2, 2, 3, 3, 3, 4, 4}

Are there any other options? No.
Keep in mind that the sum of the 7 integers must be 21 (since the mean is 3, the sum must be such that we get 3 when we divide the sum by 7)
In the last set I listed, I took two 3's (with a sum of 6) from the first set and replaced them with a 2 and a 4 (which also has a sum of 6).
Doing this means the mean remains 3.

From here, we MIGHT consider taking {2, 2, 3, 3, 3, 4, 4} and replacing two 3's with a 2 and a 4 to get: {2, 2, 2, 3, 4, 4, 4}.
HOWEVER, the mode of this new set is no longer 3 (the modeS are 2 and 4).
So, this new set does not meet the given conditions.

So, there are only 2 possible sets that meet the given conditions:
Set 1: {2, 3, 3, 3, 3, 3, 4}
Set 2: {2, 2, 3, 3, 3, 4, 4}

Now onto the question...
Quantity A: The third number in the set when the numbers are arranged in ascending order
Quantity B: The fifth number in the set when the numbers are arranged in ascending order

Let's consider each possible set separately...

Set 1: {2, 3, 3, 3, 3, 3, 4}
We get:
Quantity A: 3
Quantity B: 3
The two quantities are EQUAL

Set 2: {2, 2, 3, 3, 3, 4, 4}
We get:
Quantity A: 3
Quantity B: 3
The two quantities are EQUAL

Answer:
Show: ::
C


RELATED VIDEO FROM OUR COURSE
avatar
Intern
Intern
Joined: 08 Sep 2019
Posts: 11
Own Kudos [?]: 10 [0]
Given Kudos: 0
Send PM
Re: A set of 7 integers has a range of 2, an average of 3, and a [#permalink]
1
the average = 3
the mode = 3
range = 2
the sum = 7*3 = 21
we will find the maximum and minimum that makes the range = 2
and with a multiple of 3 that makes the sum = 21
we know the average is 3 so we will have these choices for the min value = {-2,-1,1,2}
1 will work because it makes the maximum = 3
so the range will be 3-1 = 2 .
and the set will be
{1 ,2,3,3,3,3,3,3}
mode 3
average : 3
sum =21
range : min-max = 3-1 = 2
the ans : c .
Senior Manager
Senior Manager
Joined: 17 Aug 2019
Posts: 381
Own Kudos [?]: 200 [0]
Given Kudos: 96
Send PM
Re: A set of 7 integers has a range of 2, an average of 3, and a [#permalink]
Hello
I got another set but I don't know what is my mistake:
3, 3, 3, 3, 4, 4, 5
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Own Kudos [?]: 12196 [0]
Given Kudos: 136
Send PM
Re: A set of 7 integers has a range of 2, an average of 3, and a [#permalink]
2
Asmakan wrote:
Hello
I got another set but I don't know what is my mistake:
3, 3, 3, 3, 4, 4, 5


GIVEN: A set of 7 integers has a range of 2, an average of 3, and a mode of 3.
Your seven numbers don't have an average of 3.
I have a feeling you and may have confused average with median.
avatar
Intern
Intern
Joined: 25 May 2020
Posts: 7
Own Kudos [?]: 7 [0]
Given Kudos: 0
Send PM
Re: A set of 7 integers has a range of 2, an average of 3, and a [#permalink]
1
Asmakan wrote:
Hello
I got another set but I don't know what is my mistake:
3, 3, 3, 3, 4, 4, 5



You can't select this data as the sum of the number is 25, and the average not equals to 3.
User avatar
GRE Prep Club Legend
GRE Prep Club Legend
Joined: 07 Jan 2021
Posts: 5035
Own Kudos [?]: 74 [0]
Given Kudos: 0
Send PM
Re: A set of 7 integers has a range of 2, an average of 3, and a [#permalink]
Hello from the GRE Prep Club BumpBot!

Thanks to another GRE Prep Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
Prep Club for GRE Bot
Re: A set of 7 integers has a range of 2, an average of 3, and a [#permalink]
Moderators:
GRE Instructor
84 posts
GRE Forum Moderator
37 posts
Moderator
1111 posts
GRE Instructor
234 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne