November 17, 2018 November 17, 2018 07:00 AM PST 09:00 AM PST Nov. 17, 7 AM PST. Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT. November 17, 2018 November 17, 2018 09:00 AM PST 11:00 AM PST Join the Quiz Saturday November 17th, 9 AM PST. The Quiz will last approximately 2 hours. Make sure you are on time or you will be at a disadvantage.
Author 
Message 
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 50613

Question Stats:
51% (01:13) correct 49% (01:16) wrong based on 437 sessions
HideShow timer Statistics
The ratio of the number of employees of three companies X, Y and Z is 3:4:8, respectively. Is the average age of all employees in these companies less than 40 years? (1) The total age of all the employees in these companies is 600. (2) The average age employees in X, Y, and Z, is 40, 20, and 50, respectively.
Official Answer and Stats are available only to registered users. Register/ Login.
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
What are GMAT Club Tests? Extrahard Quant Tests with Brilliant Analytics



Math Expert
Joined: 02 Sep 2009
Posts: 50613

Re M2518
[#permalink]
Show Tags
16 Sep 2014, 00:23
Official Solution: Given that the ratio of the number of employees is \(3x:4x:8x\), for some positive multiple \(x\). The questions asks whether \((average \ age)=\frac{(total \ age)}{(number \ of \ employees)} \lt 40\), or whether \(\frac{(total \ age)}{3x+4x+8x} \lt 40\), which is the same as: is \((total \ age) \lt 600x\)? (1) The total age of all the employees in these companies is 600. The question becomes: is \(600 \lt 600x\)? Or is \(1 \lt x\). We don't know that: if \(x=1\), then the answer is NO but if \(x \gt 1\), then the answer is YES. Not sufficient. (2) The average age employees in X, Y, and Z, is 40, 20, and 50, respectively. \((total \ age)=40*3x+20*4x+50*8x=600x\), so the answer to the question is NO. Sufficient. Answer: B
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
What are GMAT Club Tests? Extrahard Quant Tests with Brilliant Analytics



Intern
Joined: 28 Aug 2014
Posts: 10

Re: M2518
[#permalink]
Show Tags
19 Oct 2014, 23:50
I didnt get the solution right! can you elaborate more with any other example.



Math Expert
Joined: 02 Sep 2009
Posts: 50613

Re: M2518
[#permalink]
Show Tags
20 Oct 2014, 03:13



Intern
Joined: 28 Aug 2014
Posts: 10

Re: M2518
[#permalink]
Show Tags
20 Oct 2014, 03:20
the second statement in particular; (2) The average age employees in X, Y, and Z, is 40, 20, and 50, respectively. (total \ age)=40*3x+20*4x+50*8x=600x, so the answer to the question is NO. Sufficient.
we cannot find the answer from this statement, so how come we say its sufficient.
i opted for E because its not possible to get a single solution from both the statements.
how come the answer is B?



Math Expert
Joined: 02 Sep 2009
Posts: 50613

Re: M2518
[#permalink]
Show Tags
20 Oct 2014, 03:28
sriharsha63 wrote: the second statement in particular; (2) The average age employees in X, Y, and Z, is 40, 20, and 50, respectively. (total \ age)=40*3x+20*4x+50*8x=600x, so the answer to the question is NO. Sufficient.
we cannot find the answer from this statement, so how come we say its sufficient.
i opted for E because its not possible to get a single solution from both the statements.
how come the answer is B? This is an Yes/No DS question. In a Yes/No Data Sufficiency questions, statement(s) is sufficient if the answer is “always yes” or “always no” while a statement(s) is insufficient if the answer is "sometimes yes" and "sometimes no". The question asks: is the average age of all employees in these companies less than 40 years? As shown in the solution this is the same as asking is \((total \ age) \lt 600x\)? The second statement says that \((total \ age)=600x\), thus the asnwer to the question is NO. Hope it's clear.
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
What are GMAT Club Tests? Extrahard Quant Tests with Brilliant Analytics



Intern
Joined: 28 Aug 2014
Posts: 10

Re: M2518
[#permalink]
Show Tags
20 Oct 2014, 04:21
thanks Bunuel, it makes sense now. I wasnt aware about the yes/no DS question!!



Intern
Joined: 15 Jul 2014
Posts: 10

Re: M2518
[#permalink]
Show Tags
22 Oct 2014, 21:11
(1) The total age of all the employees in these companies is 600. The question becomes: is 600 \lt 600x? Or is 1 \lt x. We don't know that: if x=1, then the answer is NO but if x \gt 1, then the answer is YES. Not sufficient.
I dont understand why you ruled out Statement 1. We know that x>1 since there is a given ratio for the employees. isnt that sufficient?



Math Expert
Joined: 02 Sep 2009
Posts: 50613

Re: M2518
[#permalink]
Show Tags
22 Oct 2014, 22:58



Intern
Joined: 09 Mar 2013
Posts: 10

Re: M2518
[#permalink]
Show Tags
22 Dec 2014, 09:45
I did this way B) The ratio of the employees are 3:4:8 and the average age are 40,20 and 50. If you look, more no. of people are above 40 years old. So obviously average will be greater than 40 so the answer has to be N0. B is the answer Bunuel wrote: kritiu wrote: (1) The total age of all the employees in these companies is 600. The question becomes: is 600 \lt 600x? Or is 1 \lt x. We don't know that: if x=1, then the answer is NO but if x \gt 1, then the answer is YES. Not sufficient.
I dont understand why you ruled out Statement 1. We know that x>1 since there is a given ratio for the employees. isnt that sufficient? We don't know whether x > 1. The ratio could be 3:4:8, which is if x = 1.



Verbal Forum Moderator
Joined: 15 Apr 2013
Posts: 184
Location: India
Concentration: General Management, Marketing
GMAT Date: 11232015
GPA: 3.6
WE: Science (Other)

Re: M2518
[#permalink]
Show Tags
13 Nov 2015, 06:07
Hello Bunuel,
Don't you think OA needs to be edited for this question:
Question Stem:
The ratio of the number of employees of three companies X, Y and Z is 3:4:8, respectively. Is the average age of all employees in these companies less than 40 years?
Analysis:
Ratio of number of employees: X : Y: Z 3x: 4x: 8x = 15x  (A)
Age Average/Individual: Unknown
Is average age less than 40????
Statements are as follows:
(1) The total age of all the employees in these companies is 600
Average age = Total age/ N
Here N needs to be at least 15 because X can not be less than 01. So 600/15 =40
Hence average age needs to be 40 or more.
Answer to the question "Is the average age of all employees in these companies less than 40 years" is obviously NO.
(2) The average age employees in X, Y, and Z, is 40, 20, and 50, respectively.
Analysis for this statement already done by you.
So the answer to this question needs to be D.
Please suggest that whether my analysis for statement 01 is correct.
Thanks



Intern
Joined: 23 Aug 2015
Posts: 2

Re: M2518
[#permalink]
Show Tags
13 Nov 2015, 19:56
The x can't small than 1 right? the # of people at each company has to be integer...



Verbal Forum Moderator
Joined: 15 Apr 2013
Posts: 184
Location: India
Concentration: General Management, Marketing
GMAT Date: 11232015
GPA: 3.6
WE: Science (Other)

Re: M2518
[#permalink]
Show Tags
13 Nov 2015, 21:28
Right, that's what make statement 01 sufficient I guess



Retired Moderator
Joined: 23 Sep 2015
Posts: 382
Location: France
GMAT 1: 690 Q47 V38 GMAT 2: 700 Q48 V38
WE: Real Estate (Mutual Funds and Brokerage)

Re: M2518
[#permalink]
Show Tags
29 Dec 2015, 05:26
WillGetIt wrote: Right, that's what make statement 01 sufficient I guess For statement 1, the average is only 40 if there are 15 people, hence Bunuel's x = 1. But if x = 2 the number of employees is no longer 15 but 3(2):4(2):8(2) = 30 Then the average will be 600/30 = 20 so statement 1 is insufficient
_________________
New Application Tracker : update your school profiles instantly!



Retired Moderator
Joined: 23 Sep 2015
Posts: 382
Location: France
GMAT 1: 690 Q47 V38 GMAT 2: 700 Q48 V38
WE: Real Estate (Mutual Funds and Brokerage)

Re: M2518
[#permalink]
Show Tags
29 Dec 2015, 05:30
WillGetIt wrote: Hello Bunuel,
Don't you think OA needs to be edited for this question:
Question Stem:
The ratio of the number of employees of three companies X, Y and Z is 3:4:8, respectively. Is the average age of all employees in these companies less than 40 years?
Analysis:
Ratio of number of employees: X : Y: Z 3x: 4x: 8x = 15x  (A)
Age Average/Individual: Unknown
Is average age less than 40????
Statements are as follows:
(1) The total age of all the employees in these companies is 600
Average age = Total age/ N
Here N needs to be at least 15 because X can not be less than 01. So 600/15 =40
Hence average age needs to be 40 or moreLESS.
Answer to the question "Is the average age of all employees in these companies less than 40 years" is obviously NO MAYBE.
(2) The average age employees in X, Y, and Z, is 40, 20, and 50, respectively.
Analysis for this statement already done by you.
So the answer to this question needs to be D.
Please suggest that whether my analysis for statement 01 is correct.
Thanks For statement 1, the average is only 40 if there are 15 people, hence Bunuel's x = 1. But if x = 2 the number of employees is no longer 15 but 3(2):4(2):8(2) = 30 Then the average will be 600/30 = 20 so statement 1 is insufficient
_________________
New Application Tracker : update your school profiles instantly!



Intern
Joined: 26 Jun 2012
Posts: 6

Given that the ratio of the number of employees is 3x:4x:8x3x:4x:8x, for some positive multiple xx.
The questions asks whether (average age)=(total age)(number of employees)<40(average age)=(total age)(number of employees)<40, or whether (total age)3x+4x+8x<40(total age)3x+4x+8x<40, which is the same as: is (total age)<600x(total age)<600x?
(1) The total age of all the employees in these companies is 600. The question becomes: is 600<600x600<600x? Or is 1<x1<x. We don't know that: if x=1x=1, then the answer is NO but if x>1x>1, then the answer is YES. Not sufficient.
(2) The average age employees in X, Y, and Z, is 40, 20, and 50, respectively. (total age)=40∗3x+20∗4x+50∗8x=600x(total age)=40∗3x+20∗4x+50∗8x=600x, so the answer to the question is NO. Sufficient.
My solution  1) not sufficient 2) lets take minimum ratio 3:4:8 total age= 3*40+4*20+8*50 =600 so average= 600 /15 =40 (for minimum ratio) 40 is not less than 40 wrong
take next ratio multiplied by 2 lets take minimum ratio 6:8:16 then we get ratio < 40 correct two different solutions so answer is E even if we combine both two cases 1 &2 Please correct me if i am wrong



Math Expert
Joined: 02 Sep 2009
Posts: 50613

Re: M2518
[#permalink]
Show Tags
04 Jan 2017, 00:33
ashokingmat wrote: Given that the ratio of the number of employees is 3x:4x:8x3x:4x:8x, for some positive multiple xx.
The questions asks whether (average age)=(total age)(number of employees)<40(average age)=(total age)(number of employees)<40, or whether (total age)3x+4x+8x<40(total age)3x+4x+8x<40, which is the same as: is (total age)<600x(total age)<600x?
(1) The total age of all the employees in these companies is 600. The question becomes: is 600<600x600<600x? Or is 1<x1<x. We don't know that: if x=1x=1, then the answer is NO but if x>1x>1, then the answer is YES. Not sufficient.
(2) The average age employees in X, Y, and Z, is 40, 20, and 50, respectively. (total age)=40∗3x+20∗4x+50∗8x=600x(total age)=40∗3x+20∗4x+50∗8x=600x, so the answer to the question is NO. Sufficient.
My solution  1) not sufficient 2) lets take minimum ratio 3:4:8 total age= 3*40+4*20+8*50 =600 so average= 600 /15 =40 (for minimum ratio) 40 is not less than 40 wrong
take next ratio multiplied by 2 lets take minimum ratio 6:8:16 then we get ratio < 40 correct two different solutions so answer is E even if we combine both two cases 1 &2 Please correct me if i am wrong How did you get the red part? (40∗6+20∗8+50∗16)/(6 + 8 + 16) = 40, not less than 40.
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
What are GMAT Club Tests? Extrahard Quant Tests with Brilliant Analytics



Intern
Joined: 12 Mar 2017
Posts: 6
Location: India
GPA: 2.8

Re: M2518
[#permalink]
Show Tags
12 Jul 2017, 02:45
Hi. Why is the first statement insufficient? We basically have been given total age. Dividing that with the sum of ratio given is enough to deduce that the avg age of all employees = 40 yrs.
I answered it as D.



Math Expert
Joined: 02 Sep 2009
Posts: 50613

Re: M2518
[#permalink]
Show Tags
12 Jul 2017, 05:15



Senior Manager
Joined: 31 May 2017
Posts: 321

Re: M2518
[#permalink]
Show Tags
13 Mar 2018, 16:57
Interesting question. I answered D assuming the number of employees as 15 i.e x=1 in the first option. Now i get what i missed to consider. Correct answer is B
_________________
Please give kudos if it helps
Resources Ultimate GMAT Quantitative Megathread  ALL YOU NEED FOR QUANT ! ! !  SC Blogs by Magoosh  How to improve your verbal score  Things i wish i could've done earlier  Ultimate Q51 Guide







Go to page
1 2
Next
[ 21 posts ]



