GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 23 Oct 2019, 21:30 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.  Is the average (arithmetic mean) of 5 different positive integers at

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:

Hide Tags

Manager  B
Joined: 21 Feb 2012
Posts: 67
Concentration: Finance, General Management
GMAT 1: 600 Q49 V23 GPA: 3.8
WE: Information Technology (Computer Software)
Is the average (arithmetic mean) of 5 different positive integers at  [#permalink]

Show Tags

8
36 00:00

Difficulty:   25% (medium)

Question Stats: 67% (01:00) correct 33% (01:02) wrong based on 612 sessions

HideShow timer Statistics

Is the average (arithmetic mean) of 5 different positive integers at least 30?

(1) Each of the integers is a multiple of 10
(2) The sum of the 5 integers is 160
Math Expert V
Joined: 02 Sep 2009
Posts: 58465
Re: Is the average (arithmetic mean) of 5 different positive integers at  [#permalink]

Show Tags

7
8
Is the average (arithmetic mean) of 5 different positive integers at least 30?

It's almost always better to express the average in terms of the sum. The question basically asks whether the sum of 5 different positive integers is at least 5*30=150.

(1) Each of the integers is a multiple of 10 --> the least values of these 5 different positive integers are: 10, 20, 30, 40, and 50 --> the sum = 150. Sufficient.

(2) The sum of the 5 integers is 160. Directly answers the question. Sufficient.

_________________
General Discussion
Manager  Joined: 10 Jan 2011
Posts: 114
Location: India
GMAT Date: 07-16-2012
GPA: 3.4
WE: Consulting (Consulting)
Re: Is the average (arithmetic mean) of 5 different positive integers at  [#permalink]

Show Tags

Bunuel wrote:
Is the average (arithmetic mean) of 5 different positive integers at least 30?

It's almost always better to express the average in terms of the sum. The question basically asks whether the sum of 5 different positive integers is at least 5*30=150.

(1) Each of the integers is a multiple of 10 --> the least values of these 5 different positive integers are: 10, 20, 30, 40, and 50 --> the sum = 150. Sufficient.

(2) The sum of the 5 integers is 160. Directly answers the question. Sufficient.

Bunuel... nice way to explain.

However, don't you think statement A and B contradicts each other.

For example, As per statement 1, 5 numbers are multiple of 10; hence average should be mid number. (In your list 30 is the average)

As per statement 2, The average is 160/5 = 32. Now 32 is not the multiple of 10. By no means we can get 32 as average and 5 numbers multiple of 10

Please explain, am I missing something as this is GMAT prep problem
_________________
-------Analyze why option A in SC wrong-------
Math Expert V
Joined: 02 Sep 2009
Posts: 58465
Re: Is the average (arithmetic mean) of 5 different positive integers at  [#permalink]

Show Tags

1
nishtil wrote:
Bunuel wrote:
Is the average (arithmetic mean) of 5 different positive integers at least 30?

It's almost always better to express the average in terms of the sum. The question basically asks whether the sum of 5 different positive integers is at least 5*30=150.

(1) Each of the integers is a multiple of 10 --> the least values of these 5 different positive integers are: 10, 20, 30, 40, and 50 --> the sum = 150. Sufficient.

(2) The sum of the 5 integers is 160. Directly answers the question. Sufficient.

Bunuel... nice way to explain.

However, don't you think statement A and B contradicts each other.

For example, As per statement 1, 5 numbers are multiple of 10; hence average should be mid number. (In your list 30 is the average)

As per statement 2, The average is 160/5 = 32. Now 32 is not the multiple of 10. By no means we can get 32 as average and 5 numbers multiple of 10

Please explain, am I missing something as this is GMAT prep problem

We are not told that the integers are evenly spaced so it's not necessary that the average is the middle number (in my example, yes, I consider evenly spaced set, but it's just one of the cases). For example the set could be 10, 20, 30, 40, and 60 --> sum=160 --> average=160/5=32.

Hope it's clear.
_________________
Manager  Joined: 05 Nov 2012
Posts: 138
Re: Is the average (arithmetic mean) of 5 different positive integers at  [#permalink]

Show Tags

1
Bunuel wrote:
Is the average (arithmetic mean) of 5 different positive integers at least 30?

It's almost always better to express the average in terms of the sum. The question basically asks whether the sum of 5 different positive integers is at least 5*30=150.

(1) Each of the integers is a multiple of 10 --> the least values of these 5 different positive integers are: 10, 20, 30, 40, and 50 --> the sum = 150. Sufficient.

(2) The sum of the 5 integers is 160. Directly answers the question. Sufficient.

why cannot we consider 0,10,20,30,40? Isn't 0 taken as both positive and negative?
Math Expert V
Joined: 02 Sep 2009
Posts: 58465
Re: Is the average (arithmetic mean) of 5 different positive integers at  [#permalink]

Show Tags

2
1
Amateur wrote:
Bunuel wrote:
Is the average (arithmetic mean) of 5 different positive integers at least 30?

It's almost always better to express the average in terms of the sum. The question basically asks whether the sum of 5 different positive integers is at least 5*30=150.

(1) Each of the integers is a multiple of 10 --> the least values of these 5 different positive integers are: 10, 20, 30, 40, and 50 --> the sum = 150. Sufficient.

(2) The sum of the 5 integers is 160. Directly answers the question. Sufficient.

why cannot we consider 0,10,20,30,40? Isn't 0 taken as both positive and negative?

Positive numbers are greater than zero and negative numbers are less than zero. Zero is neither positive nor negative.
_________________
Intern  Joined: 17 Oct 2012
Posts: 49
Re: Is the average (arithmetic mean) of 5 different positive integers at  [#permalink]

Show Tags

Bunuel wrote:
Is the average (arithmetic mean) of 5 different positive integers at least 30?

It's almost always better to express the average in terms of the sum. The question basically asks whether the sum of 5 different positive integers is at least 5*30=150.

(1) Each of the integers is a multiple of 10 --> the least values of these 5 different positive integers are: 10, 20, 30, 40, and 50 --> the sum = 150. Sufficient.

(2) The sum of the 5 integers is 160. Directly answers the question. Sufficient.

One question: is zero not considered as a multiple of any number?
Math Expert V
Joined: 02 Sep 2009
Posts: 58465
Re: Is the average (arithmetic mean) of 5 different positive integers at  [#permalink]

Show Tags

BankerRUS wrote:
Bunuel wrote:
Is the average (arithmetic mean) of 5 different positive integers at least 30?

It's almost always better to express the average in terms of the sum. The question basically asks whether the sum of 5 different positive integers is at least 5*30=150.

(1) Each of the integers is a multiple of 10 --> the least values of these 5 different positive integers are: 10, 20, 30, 40, and 50 --> the sum = 150. Sufficient.

(2) The sum of the 5 integers is 160. Directly answers the question. Sufficient.

One question: is zero not considered as a multiple of any number?

Yes, 0 is a multiple of every integer except 0 itself.
_________________
Intern  B
Joined: 15 Jul 2017
Posts: 1
Re: Is the average (arithmetic mean) of 5 different positive integers at  [#permalink]

Show Tags

Bunuel wrote:
BankerRUS wrote:
Bunuel wrote:
Is the average (arithmetic mean) of 5 different positive integers at least 30?

It's almost always better to express the average in terms of the sum. The question basically asks whether the sum of 5 different positive integers is at least 5*30=150.

(1) Each of the integers is a multiple of 10 --> the least values of these 5 different positive integers are: 10, 20, 30, 40, and 50 --> the sum = 150. Sufficient.

(2) The sum of the 5 integers is 160. Directly answers the question. Sufficient.

One question: is zero not considered as a multiple of any number?

Yes, 0 is a multiple of every integer except 0 itself.

Why are we not considering 1 as multiple of 10?
Math Expert V
Joined: 02 Sep 2009
Posts: 58465
Re: Is the average (arithmetic mean) of 5 different positive integers at  [#permalink]

Show Tags

shubhdeora wrote:
Why are we not considering 1 as multiple of 10?

1 is a factor (divisor) of 10, not a multiple of 10.
_________________
Intern  Joined: 20 Aug 2018
Posts: 25
Re: Is the average (arithmetic mean) of 5 different positive integers at  [#permalink]

Show Tags

A more detailed explanation can be found here:

Average = (SUM of terms)/(# of terms)

Since we're told what the average is, the real question becomes, "What is the sum of the terms?" That's the information we need to know in order to answer the question.

Statement (1) First, a quick point - zero is an integer, and zero is also a multiple of 10 (10*0 = 0), but since zero is not a POSITIVE integer (it's neither negative nor positive), it can't one of the 5 numbers.

The smallest possible numbers, therefore, are 10, 20, 30, 40, 50. We can (easily) find the sum, so statement (1) gives us sufficient info to answer the question.

Statement (2) clearly tells us exactly what we need to know, as well.

_________________

Originally posted by CrushGMAT on 24 Nov 2018, 18:10.
Last edited by CrushGMAT on 25 Nov 2018, 13:27, edited 1 time in total. Re: Is the average (arithmetic mean) of 5 different positive integers at   [#permalink] 24 Nov 2018, 18:10
Display posts from previous: Sort by

Is the average (arithmetic mean) of 5 different positive integers at

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics

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