Currently, y percent of the members on the finance committee are women and next month, z percent of the men on the finance committee will resign. If no other personnel changes occur, then after the resignations next month, the men who remain on the finance committee will represent what percent of the total finance committee members?
How do you solve it in less than or around 2 minutes?
[spoiler]Answer: (100)(100 - z)(100 - y)/ (100)(100)-z(100-y)[/spoiler]
Percents- 700-800
This topic has expert replies
- limestone
- Master | Next Rank: 500 Posts
- Posts: 307
- Joined: Sun Jul 11, 2010 7:52 pm
- Thanked: 36 times
- Followed by:1 members
- GMAT Score:640
Just thoroughly understand percentage concept, and solve it as quick as you can.
Percentage of Women y/100
then that of men 100/100 - y/100 = (100-y)/100
z% resign then percentage of men will resign: (100-y)/100* z/100
that of remaining men:(100-y)/100* (100-z)/100
Try to remember some quick rules: women = y/100 then men = (100-y)/100
Here we have a product of percentage of men and percentage of not resigning
(100-y)/100_______ X ___________ (100-z)/100
The rule give you 2 bold phrases quickly.
Now come to the remaining members of the committee:
100/100 - (100-y)/100* z/100 = 100- z*(100-y)/100
Ratio of remaining men / remaining members
= (100-y)/100* (100-z)/100____/____(100- z*(100-y)/100)
= (100-y)*(100-z)/100_____/_____(100-z*(100-y))
= (100-y)*(100-z)____/_____100*(100-z*(100-y))
Change from ratio to percentage, multiply 100:
100____*___(100-y)*(100-z)____/_____100*(100-z*(100-y))
Percentage of Women y/100
then that of men 100/100 - y/100 = (100-y)/100
z% resign then percentage of men will resign: (100-y)/100* z/100
that of remaining men:(100-y)/100* (100-z)/100
Try to remember some quick rules: women = y/100 then men = (100-y)/100
Here we have a product of percentage of men and percentage of not resigning
(100-y)/100_______ X ___________ (100-z)/100
The rule give you 2 bold phrases quickly.
Now come to the remaining members of the committee:
100/100 - (100-y)/100* z/100 = 100- z*(100-y)/100
Ratio of remaining men / remaining members
= (100-y)/100* (100-z)/100____/____(100- z*(100-y)/100)
= (100-y)*(100-z)/100_____/_____(100-z*(100-y))
= (100-y)*(100-z)____/_____100*(100-z*(100-y))
Change from ratio to percentage, multiply 100:
100____*___(100-y)*(100-z)____/_____100*(100-z*(100-y))
"There is nothing either good or bad - but thinking makes it so" - Shakespeare.
- lavinia
- Senior | Next Rank: 100 Posts
- Posts: 48
- Joined: Mon Oct 12, 2009 5:15 am
- Thanked: 5 times
- Followed by:1 members
Hi Limestone,
First of all thank you for your answer. I woud like to mention that your answer choice is not the correct one. If you see it is:100(100-z)(100-y)/ 100 squared -z(100-y)
My explanation is similar to yours, but I feel that your answer is not the correct one or I'm wrong:)
Current W: y/100
Current M: (100-y)/100
Resign M: [z/100*(100-y)]/100=z(100-y)/ 100 squared
Remain M: Current M - Resign M= (100-y)/100- [z(100-y)]/100squared= (100-y)(100-z)/ 100 squared
Total people remain: 100/100- Resign M= 100/100- z(100-y)/100 squared= [100squared-z(100-y)] /100squared
Part=?% * Whole
(Remain M/ Total people remain)*100=?
[100(100-y)(100-z)]/ 100 squared * 100squared/ 100 squared-z(100-y)
Answer: 100(100-y)(100-z)/ 100 squared- z(100-y)
Is it a strategy that it is not time consuming for this kind of problem or we just solvit it? In my case, it takes aroud 3 minutes.
Thanks again Limestone!!!
First of all thank you for your answer. I woud like to mention that your answer choice is not the correct one. If you see it is:100(100-z)(100-y)/ 100 squared -z(100-y)
My explanation is similar to yours, but I feel that your answer is not the correct one or I'm wrong:)
Current W: y/100
Current M: (100-y)/100
Resign M: [z/100*(100-y)]/100=z(100-y)/ 100 squared
Remain M: Current M - Resign M= (100-y)/100- [z(100-y)]/100squared= (100-y)(100-z)/ 100 squared
Total people remain: 100/100- Resign M= 100/100- z(100-y)/100 squared= [100squared-z(100-y)] /100squared
Part=?% * Whole
(Remain M/ Total people remain)*100=?
[100(100-y)(100-z)]/ 100 squared * 100squared/ 100 squared-z(100-y)
Answer: 100(100-y)(100-z)/ 100 squared- z(100-y)
Is it a strategy that it is not time consuming for this kind of problem or we just solvit it? In my case, it takes aroud 3 minutes.
Thanks again Limestone!!!
limestone wrote:Just thoroughly understand percentage concept, and solve it as quick as you can.
Percentage of Women y/100
then that of men 100/100 - y/100 = (100-y)/100
z% resign then percentage of men will resign: (100-y)/100* z/100
that of remaining men:(100-y)/100* (100-z)/100
Try to remember some quick rules: women = y/100 then men = (100-y)/100
Here we have a product of percentage of men and percentage of not resigning
(100-y)/100_______ X ___________ (100-z)/100
The rule give you 2 bold phrases quickly.
Now come to the remaining members of the committee:
100/100 - (100-y)/100* z/100 = 100- z*(100-y)/100
Ratio of remaining men / remaining members
= (100-y)/100* (100-z)/100____/____(100- z*(100-y)/100)
= (100-y)*(100-z)/100_____/_____(100-z*(100-y))
= (100-y)*(100-z)____/_____100*(100-z*(100-y))
Change from ratio to percentage, multiply 100:
100____*___(100-y)*(100-z)____/_____100*(100-z*(100-y))
- 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
I would plug in values:lavinia wrote:Currently, y percent of the members on the finance committee are women and next month, z percent of the men on the finance committee will resign. If no other personnel changes occur, then after the resignations next month, the men who remain on the finance committee will represent what percent of the total finance committee members?
How do you solve it in less than or around 2 minutes?
[spoiler]Answer: (100)(100 - z)(100 - y)/ (100)(100)-z(100-y)[/spoiler]
100 members
y = 20
20 women, 80 men
z = 50
So .5*80 = 40 men resign
80-40 = 40 men left
100-40 = 60 members left
40/60 = 66 2/3%
Correct answer: (100)(100 - z)(100 - y) / (100)(100)-z(100-y)
= 100(100-50)(100-20) / (100)(100)-50(100-20)
= 400000/6000
= 400/6 = 66 2/3
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
- limestone
- Master | Next Rank: 500 Posts
- Posts: 307
- Joined: Sun Jul 11, 2010 7:52 pm
- Thanked: 36 times
- Followed by:1 members
- GMAT Score:640
Thanks Lavinia
I made a mistake from this step:
100/100 - (100-y)/100* z/100 = 100^2- z*(100-y)/100
Then the answer should be: (after I have redone it again)
100*(100-y)*(100-z)/(100^2-z*(100-y))
So many No. and x/y confused me. Lol.
I think only frequent practice can help us solve this problem both quickly and precisely. It also took me more than 2 minutes ( In the real test, hope I can solve other questions quickly to spare the time for such time consuming questions like this)
Thanks again buddy.
[/quote]
I made a mistake from this step:
Actually, it should beNow come to the remaining members of the committee:
100/100 - (100-y)/100* z/100 = 100- z*(100-y)/100
100/100 - (100-y)/100* z/100 = 100^2- z*(100-y)/100
Then the answer should be: (after I have redone it again)
100*(100-y)*(100-z)/(100^2-z*(100-y))
So many No. and x/y confused me. Lol.
I think only frequent practice can help us solve this problem both quickly and precisely. It also took me more than 2 minutes ( In the real test, hope I can solve other questions quickly to spare the time for such time consuming questions like this)
Thanks again buddy.
[/quote]
"There is nothing either good or bad - but thinking makes it so" - Shakespeare.
- limestone
- Master | Next Rank: 500 Posts
- Posts: 307
- Joined: Sun Jul 11, 2010 7:52 pm
- Thanked: 36 times
- Followed by:1 members
- GMAT Score:640
Thanks Mitch for your nice plug-in method. It's quick, less time consuming and it really helps.
"There is nothing either good or bad - but thinking makes it so" - Shakespeare.
- lavinia
- Senior | Next Rank: 100 Posts
- Posts: 48
- Joined: Mon Oct 12, 2009 5:15 am
- Thanked: 5 times
- Followed by:1 members
Thanks GMATGuruNY!
For this kind of question- how do I choose the smart numbers? Are some rules for picking the numbers that I can apply them for other similar problems?
For this kind of question- how do I choose the smart numbers? Are some rules for picking the numbers that I can apply them for other similar problems?
GMATGuruNY wrote:I would plug in values:lavinia wrote:Currently, y percent of the members on the finance committee are women and next month, z percent of the men on the finance committee will resign. If no other personnel changes occur, then after the resignations next month, the men who remain on the finance committee will represent what percent of the total finance committee members?
How do you solve it in less than or around 2 minutes?
[spoiler]Answer: (100)(100 - z)(100 - y)/ (100)(100)-z(100-y)[/spoiler]
100 members
y = 20
20 women, 80 men
z = 50
So .5*80 = 40 men resign
80-40 = 40 men left
100-40 = 60 members left
40/60 = 66 2/3%
Correct answer: (100)(100 - z)(100 - y) / (100)(100)-z(100-y)
= 100(100-50)(100-20) / (100)(100)-50(100-20)
= 400000/6000
= 400/6 = 66 2/3
How did you reach the values of Women 20 and Men 80. Would appreciate your help
Regards
Regards
GMATGuruNY wrote:I would plug in values:lavinia wrote:Currently, y percent of the members on the finance committee are women and next month, z percent of the men on the finance committee will resign. If no other personnel changes occur, then after the resignations next month, the men who remain on the finance committee will represent what percent of the total finance committee members?
How do you solve it in less than or around 2 minutes?
[spoiler]Answer: (100)(100 - z)(100 - y)/ (100)(100)-z(100-y)[/spoiler]
100 members
y = 20
20 women, 80 men
z = 50
So .5*80 = 40 men resign
80-40 = 40 men left
100-40 = 60 members left
40/60 = 66 2/3%
Correct answer: (100)(100 - z)(100 - y) / (100)(100)-z(100-y)
= 100(100-50)(100-20) / (100)(100)-50(100-20)
= 400000/6000
= 400/6 = 66 2/3
GMAT/MBA Expert
- [email protected]
- Elite Legendary Member
- Posts: 10392
- Joined: Sun Jun 23, 2013 6:38 pm
- Location: Palo Alto, CA
- Thanked: 2867 times
- Followed by:511 members
- GMAT Score:800
Hi lavinia,
The TESTING VALUES approach is great for these types of questions because it allows you to do quick basic calculations and avoid long-winded algebra. Round numbers tend to be best in these situations (the word "percent" tips you off that 100 would probably be a good choice)).
You did say something in your original post that worth talking about though. You shouldn't expect to spend 2 minutes (or less) on each question. That's unrealistic. Certain questions on Test Day are designed to take 3 minutes to solve and that's IF you know what what you're doing. Others require less than a minute to solve. If this question takes you 3 minutes to solve, then that's fine; by TESTING VALUES though, you should be able to do it faster.
GMAT assassins aren't born, they're made,
Rich
The TESTING VALUES approach is great for these types of questions because it allows you to do quick basic calculations and avoid long-winded algebra. Round numbers tend to be best in these situations (the word "percent" tips you off that 100 would probably be a good choice)).
You did say something in your original post that worth talking about though. You shouldn't expect to spend 2 minutes (or less) on each question. That's unrealistic. Certain questions on Test Day are designed to take 3 minutes to solve and that's IF you know what what you're doing. Others require less than a minute to solve. If this question takes you 3 minutes to solve, then that's fine; by TESTING VALUES though, you should be able to do it faster.
GMAT assassins aren't born, they're made,
Rich