Is the average(arithmetic mean) of 5 different integer atleast 30?
1) Each integer is a multiple of 10
2) The sum of 5 integer is 160
Statement 2 is sufficient(a+b+c+d+e>=30*5-->150)
I need explanation for statement 1.
Average
This topic has expert replies
-
- Senior | Next Rank: 100 Posts
- Posts: 44
- Joined: Thu Jan 03, 2013 10:30 pm
- Thanked: 4 times
a+b+c+d+e>=150
If a,b,c,d,e each is multiple of 10; the least sum of 5 different integers, multiples of 10, is:
0+10+20+30+40=100
Statement 1 is not sufficient.
(check this https://www.beatthegmat.com/is-zero-to-b ... t4268.html)
If a,b,c,d,e each is multiple of 10; the least sum of 5 different integers, multiples of 10, is:
0+10+20+30+40=100
Statement 1 is not sufficient.
(check this https://www.beatthegmat.com/is-zero-to-b ... t4268.html)
GMAT/MBA Expert
- Anju@Gurome
- GMAT Instructor
- Posts: 511
- Joined: Wed Aug 11, 2010 9:47 am
- Location: Delhi, India
- Thanked: 344 times
- Followed by:86 members
Statement 1: As the integers can be positive or negative, the mean also can be positive or negative. Hence, from this statement we can only conclude that the mean is a multiple of 10 also.paresh_patil wrote:Is the average(arithmetic mean) of 5 different integer atleast 30?
1) Each integer is a multiple of 10
2) The sum of 5 integer is 160
For example, consider the following two cases,
- {-20, -10, 0, 10, 20} ---> Mean = 0 < 30
{100, 200, 300, 400, 500} ---> Mean = 300 > 30
Statement 2: Mean of the integers = 160/5
Sufficient
The correct answer is B.
Anju Agarwal
Quant Expert, Gurome
Backup Methods : General guide on plugging, estimation etc.
Wavy Curve Method : Solving complex inequalities in a matter of seconds.
§ GMAT with Gurome § Admissions with Gurome § Career Advising with Gurome §
Quant Expert, Gurome
Backup Methods : General guide on plugging, estimation etc.
Wavy Curve Method : Solving complex inequalities in a matter of seconds.
§ GMAT with Gurome § Admissions with Gurome § Career Advising with Gurome §
- GMATGuruNY
- GMAT Instructor
- Posts: 15539
- Joined: Tue May 25, 2010 12:04 pm
- Location: New York, NY
- Thanked: 13060 times
- Followed by:1906 members
- GMAT Score:790
This question is from GMATPrep.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 five integers is 160
Please note the word in red, which was omitted from the OP: the actual question stem requires that the all of the integers be POSITIVE.
Statement 1: Each integer is a multiple of 10
Least possible values: 10, 20, 30, 40, 50.
When values are EVENLY SPACED, the average = the median.
Thus, the average here is 30.
Since the least possible average is 30, the average of the 5 integers must be at least 30.
SUFFICIENT.
Statement 2: Sum = 160.
Since average = sum/number, the average of the 5 integers can be determined.
SUFFICIENT.
The correct answer is D.
Please note the following:
When a GMAT problem asks about multiples, the problem is invariably restricted to POSITIVE INTEGERS.
Thus, we don't have to consider 0 (which is a multiple of every integer) or negative values.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
- freyesinsb
- Junior | Next Rank: 30 Posts
- Posts: 16
- Joined: Thu Aug 25, 2011 2:13 pm
When the GMAT asks "at least 30," does that mean greater than OR equal to 30? In the solution proposed by Mitch, the least possible answer for the mean was equal to 30.