Author 
Message 
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 47037

At a technology firm, employees are categorizes as either engineers or [#permalink]
Show Tags
29 Aug 2017, 23:44
Question Stats:
80% (02:04) correct 20% (02:06) wrong based on 81 sessions
HideShow timer Statistics




Target Test Prep Representative
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2669

Re: At a technology firm, employees are categorizes as either engineers or [#permalink]
Show Tags
02 Sep 2017, 07:11
Bunuel wrote: At a technology firm, employees are categorizes as either engineers or nonengineers. 80% of the engineers have a masters degree and 55% of the nonengineers have a masters degree. If 70% of all employees have a masters degree, what percent of all employees are engineers?
A. 55% B. 60% C. 65% D. 70% E. 75% We can let the total employees = 100. Thus, 70 have a master’s degree and 30 do not. We can let n = the number of engineers and create the following equation: 0.8n + 0.55(100  n) = 70 0.8n + 55  0.55n = 70 0.25n = 15 n = 60 Thus, engineers are 60% of the employees. Answer: B
_________________
Jeffery Miller
Head of GMAT Instruction
GMAT Quant SelfStudy Course
500+ lessons 3000+ practice problems 800+ HD solutions




Director
Joined: 18 Aug 2016
Posts: 631
Concentration: Strategy, Technology
GMAT 1: 630 Q47 V29 GMAT 2: 740 Q51 V38

At a technology firm, employees are categorizes as either engineers or [#permalink]
Show Tags
Updated on: 30 Aug 2017, 01:07
Bunuel wrote: At a technology firm, employees are categorizes as either engineers or nonengineers. 80% of the engineers have a masters degree and 55% of the nonengineers have a masters degree. If 70% of all employees have a masters degree, what percent of all employees are engineers?
A. 55% B. 60% C. 65% D. 70% E. 75% ...................M..............NM..............Total E...............0.8x............0.2x...............x NE............0.55y...........0.45y..............y Total.....0.8x+0.55y....0.2x+0.45y.......x+y \(0.8x+0.55y = 0.7(x+y)\) \(0.1x = 0.15y\) \(x=1.5y\) Since we have to calculate the % of engineers from all employees..eqn would be x/(x+y) \(1.5y/(1.5y+y)\) 1.5/2.5 = 60% B
_________________
We must try to achieve the best within us
Thanks Luckisnoexcuse




Manager
Status: Searching for something I've been searching..LOL
Joined: 14 Dec 2016
Posts: 63
Location: India
Concentration: Healthcare, Operations
GPA: 3.5
WE: Medicine and Health (Health Care)

Re: At a technology firm, employees are categorizes as either engineers or [#permalink]
Show Tags
30 Aug 2017, 01:01
Luckisnoexcuse wrote: Bunuel wrote: At a technology firm, employees are categorizes as either engineers or nonengineers. 80% of the engineers have a masters degree and 55% of the nonengineers have a masters degree. If 70% of all employees have a masters degree, what percent of all employees are engineers?
A. 55% B. 60% C. 65% D. 70% E. 75% M NM Total E 0.8x 0.2x x NE 0.55y 0.45y y Total 0.8x+0.55y 0.2x+0.45y x+y 0.8x+0.55y = 0.7(x+y) 0.1x = 0.15y x=1.5y 1.5/2.5 = 60%B Would you be kind enough to explain how you got the denominator in the highlighted step??? Luckisnoexcuse



Director
Joined: 18 Aug 2016
Posts: 631
Concentration: Strategy, Technology
GMAT 1: 630 Q47 V29 GMAT 2: 740 Q51 V38

At a technology firm, employees are categorizes as either engineers or [#permalink]
Show Tags
30 Aug 2017, 01:04
kill3rlook5 wrote: Luckisnoexcuse wrote: Bunuel wrote: At a technology firm, employees are categorizes as either engineers or nonengineers. 80% of the engineers have a masters degree and 55% of the nonengineers have a masters degree. If 70% of all employees have a masters degree, what percent of all employees are engineers?
A. 55% B. 60% C. 65% D. 70% E. 75% M NM Total E 0.8x 0.2x x NE 0.55y 0.45y y Total 0.8x+0.55y 0.2x+0.45y x+y 0.8x+0.55y = 0.7(x+y) 0.1x = 0.15y x=1.5y 1.5/2.5 = 60%B Would you be kind enough to explain how you got the denominator in the highlighted step??? LuckisnoexcuseSure kill3rlook5We have to calculate x/(x+y) since x = 1.5y x/(x+y) = 1.5y/(1.5y + y) = 1.5/2.5..which is 60% in % terms Hope it helps
_________________
We must try to achieve the best within us
Thanks Luckisnoexcuse



Manager
Status: Searching for something I've been searching..LOL
Joined: 14 Dec 2016
Posts: 63
Location: India
Concentration: Healthcare, Operations
GPA: 3.5
WE: Medicine and Health (Health Care)

Re: At a technology firm, employees are categorizes as either engineers or [#permalink]
Show Tags
30 Aug 2017, 01:18
Quote: Sure kill3rlook5We have to calculate x/(x+y) since x = 1.5y x/(x+y) = 1.5y/(1.5y + y) = 1.5/2.5..which is 60% in % terms Hope it helps Thanks a ton for explaining that. I was on the verge of tearing my hair trying to understand that....



SC Moderator
Joined: 22 May 2016
Posts: 1826

At a technology firm, employees are categorizes as either engineers or [#permalink]
Show Tags
30 Aug 2017, 18:01
Luckisnoexcuse wrote: Bunuel wrote: At a technology firm, employees are categorizes as either engineers or nonengineers. 80% of the engineers have a masters degree and 55% of the nonengineers have a masters degree. If 70% of all employees have a masters degree, what percent of all employees are engineers?
A. 55% B. 60% C. 65% D. 70% E. 75% ...................M..............NM..............Total E...............0.8x............0.2x...............x NE............0.55y...........0.45y..............y Total.....0.8x+0.55y....0.2x+0.45y....... x+y\(0.8x+0.55y = 0.7(x+y)\) \(0.1x = 0.15y\) \(x=1.5y\) Since we have to calculate the % of engineers from all employees..eqn would be x/(x+y) \(1.5y/(1.5y+y)\) 1.5/2.5 = 60% B I used your equation, but not your chart, and confused myself for a LONG time about total, despite the fact that I had just used both variables in a weighted average to find the ratio of x to y. I kept thinking that I had failed to account for the other 30 percent who were not included in the equation. I chose B, unconvinced. Then I saw your post. I'm still not sure I understand what happened to the other 30 percent, but I believe you. Nice work. And kudos.
_________________
In the depths of winter, I finally learned that within me there lay an invincible summer.  Albert Camus, "Return to Tipasa"



Manager
Joined: 04 May 2014
Posts: 162
Location: India
WE: Sales (Mutual Funds and Brokerage)

Re: At a technology firm, employees are categorizes as either engineers or [#permalink]
Show Tags
10 Sep 2017, 21:04
Overlapping sets problem. we can use 2X2 table.
Attachments
Screen Shot 20170911 at 9.33.11 AM.png [ 34.29 KiB  Viewed 833 times ]



Senior Manager
Status: love the club...
Joined: 24 Mar 2015
Posts: 278

Re: At a technology firm, employees are categorizes as either engineers or [#permalink]
Show Tags
10 Sep 2017, 22:14
Bunuel wrote: At a technology firm, employees are categorizes as either engineers or nonengineers. 80% of the engineers have a masters degree and 55% of the nonengineers have a masters degree. If 70% of all employees have a masters degree, what percent of all employees are engineers?
A. 55% B. 60% C. 65% D. 70% E. 75% 70 = .8x + (100  x)* .55 solving for x we can get the answer ... hope this helps cheers ..



CR Forum Moderator
Status: He came. He saw. He conquered.  Studying for the LSAT
Joined: 31 Jul 2017
Posts: 266
Location: United States
Concentration: Finance, Economics

At a technology firm, employees are categorizes as either engineers or [#permalink]
Show Tags
11 Sep 2017, 11:57
Explaining the photo below using the seesaw method: Please forgive the crudeness of the drawing! The ratio of masters degrees is 3:2 (15:10), weighted towards engineers. So, engineers comprise 60% of the company. We get this because we know 55% of non engineers have their degree, and 80% of engineers do as well, so you can determine the weight of each, given that 70% of the total company have their degree. Notice the tilt towards the engineer side, so you don't get confused with the 15 and 10.
Attachments
picture 1.png [ 13.12 KiB  Viewed 747 times ]
_________________
DDay: November 18th, 2017
Need a laugh and a break? Go here: https://gmatclub.com/forum/mentalbreakfunnyvideos270269.html




At a technology firm, employees are categorizes as either engineers or
[#permalink]
11 Sep 2017, 11:57






