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because the total number of people is both the women and men
men = n
women = n+ 75
thus total people is 2n+75
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+ Show Spoiler +It's E and not D because n/n+75 is number of men / number of women, but n/2n+75=n/n+n+75= number of men/number of men+ number women
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AHH U GOT ME
damnit its been like half a year since i've looked at SAT shit xD
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linden college is not a real college this is a fake question
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+ Show Spoiler +basically , the variables are just throwing you off i guess
plug in some numbers to see if it makes sense
alright lets say there's 100 girls and 25 guys
what D is basically saying n/ n+75
however thats not true, it's 25/125 not 25/100, hence the "2n"
it's the 25 guys over the TOTAL people, guys and girls included (125)
which in this case n=25, and 2n+75 = 125
therefore E
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thedeadhaji
39489 Posts
This is how to do this problem while taking a standardized test.
substitute 25 for n. there are 25 men enrolled. hence there are 100 women enrolled.
% men = men / total = men / (men + women) = 25/125 = 20%
A. n/(n+75)% = 25 / 100 = NO
B. n/(2n+75)% = 25 / 125 = NO
C. n/((100)(2n+75)% = 100 / (12500) = NO
D. 100n/(n+75)% = 2500 / 100 = 25% = NO
E. 100n/(2n+75)% = 2500 / 125 = 20% = YES
Key to remember is to not plug in for n with a value that appears in the prompt or the answer choices. Also you must check all 5 answers to make sure that no more than one answer is correct. If two or more answer choices are correct, plug in another number.
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thedeadhaji
39489 Posts
DO NOT WORK WITH VARIABLES.
PLUG SHIT IN
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Oh ok thanks for the explanations. So for these questions with variables, just plug and see what works?
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On April 05 2009 02:37 thedeadhaji wrote:
DO NOT WORK WITH VARIABLES.
PLUG SHIT IN
This.
The single biggest piece of advice you can get for taking these standardized math tests.
Edit:
On April 05 2009 02:47 il0seonpurpose wrote:
Oh ok thanks for the explanations. So for these questions with variables, just plug and see what works?
Yes. Eliminate the answers you immediately know aren't right. Pick easy test cases. After finding the an answer that works, check the remaining answers(out of the ones you are sure aren't wrong) to verify your solution works only for the one choice. If it works for more than that one, pick new test cases and check all the remaining answers.
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I don't see why you would plug stuff in. It makes it much quicker and simpler to think in variables. Look at the question, not the answers.
The question asks for the percentage of men enrolled.
That means 100*(men/total).
You know by simple knowledge that total is men+women.
The question gives you men=n, and women =n+75.
So total =n+(n+75)=2n+75.
So the answer is 100*(n/(2n+75))=100n/(2n+75).
Sure enough, that's one of the answers. Done, all of it easy to do in your head.
edit - I suppose it would depend on how much time you have. I've obviously never written an SAT so I don't know. If you have the time, yeah, go ahead and plug numbers to make sure.
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On April 05 2009 02:37 thedeadhaji wrote:
DO NOT WORK WITH VARIABLES.
PLUG SHIT IN
You are joking right...?
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On April 05 2009 03:04 Cambium wrote:Show nested quote +On April 05 2009 02:37 thedeadhaji wrote:
DO NOT WORK WITH VARIABLES.
PLUG SHIT IN You are joking right...?
Does it look that way?
Variables take way too much time, even in cases where you are not allowed a calculator it is pretty much always better to use simple numbers.
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On April 05 2009 03:04 Cambium wrote:Show nested quote +On April 05 2009 02:37 thedeadhaji wrote:
DO NOT WORK WITH VARIABLES.
PLUG SHIT IN You are joking right...?
If you suck at maths and don't want to learn it properly his method is by far the best.
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On April 05 2009 03:08 Ecael wrote:Show nested quote +On April 05 2009 03:04 Cambium wrote:On April 05 2009 02:37 thedeadhaji wrote:
DO NOT WORK WITH VARIABLES.
PLUG SHIT IN You are joking right...? Does it look that way? Variables take way too much time, even in cases where you are not allowed a calculator it is pretty much always better to use simple numbers.
I solved the problem in literally 3 seconds, and if I were to plug in numbers and do trial and error for all five answers, that would take at least 1 minute. Not to mention using real numbers is extremely error prone.
Variables are almost always better than numbers.
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On April 05 2009 03:08 Ecael wrote:Show nested quote +On April 05 2009 03:04 Cambium wrote:On April 05 2009 02:37 thedeadhaji wrote:
DO NOT WORK WITH VARIABLES.
PLUG SHIT IN You are joking right...? Does it look that way? Variables take way too much time, even in cases where you are not allowed a calculator it is pretty much always better to use simple numbers.
I disagree that variables take too much time. If all the questions are as simple as this one, then thinking through it in terms of variables would be much quicker than plugging numbers for every possible answer. I think the advantage of plugging numbers is guaranteed accuracy.
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On April 05 2009 03:10 Cambium wrote:Show nested quote +On April 05 2009 03:08 Ecael wrote:On April 05 2009 03:04 Cambium wrote:On April 05 2009 02:37 thedeadhaji wrote:
DO NOT WORK WITH VARIABLES.
PLUG SHIT IN You are joking right...? Does it look that way? Variables take way too much time, even in cases where you are not allowed a calculator it is pretty much always better to use simple numbers. I solved the problem in literally 3 seconds, and if I were to plug in numbers and do trial and error for all five answers, that would take at least 1 minute. Not to mention using real numbers is extremely error prone. Variables are almost always better than numbers.
This problem is one of the simplest ones for solving by variables, for this particular problem variable could be a good solution, but not in a general case. Standardized tests vary too much in terms of the kind of things they toss at you to make it work. Obviously it is best if you can recognize the problems and know whether to use variable or plugin based on the question, but if one is to rely on a single method, plug-in is more reliable imo.
I did this question by variables and by plug-in, but it wasn't a significant difference in time. A~C are obviously wrong when we regard the fact that there is a %, that cuts down most of the time necessary for plugin. (At that, D doesn't even need to be solved, you look at the numbers and it is wrong)
Not sure what you mean by using real numbers is error prone, that's why you use simple numbers that reduce complexity.
Klockan, except SATs and such are not testing your mathematical abilities. If this was say, his final on a 9th grade math class, I'd tell him to use variables. Except this is a test where you are timed, tested for consistency, and need to be efficient. I don't see how wanting to learn math is relevant at all to this.
GGQ, that's the issue. When you think that you can solve one problem with variables you tend to start going at them all with variables, but there is a wide range of question. From my test taking experiences of this kind, it is far better to rely on plugging in than to risk being drawn into that concept. The 3 seconds for this problem can change to 5 for the next, 15 for the one after, but the elimination of answers into plugging in seldom go above 3 answers needing to be tested. You are given a calculator, make best use of it.
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United States10774 Posts
On April 05 2009 02:37 thedeadhaji wrote:
DO NOT WORK WITH VARIABLES.
PLUG SHIT IN
i made the decision of using numbers or variables depending on the problem's complexity. for this one, i would just use variables because it's really rather simple. but yeah, plugging in can be extremely useful in other cases
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PLUGGING SHIT IN IS UNDERRATED
THE ONLY DOWNSIDE TO PLUGGING SHIT IN IS WHEN YOU USE NUMBERS THAT ARE TOO SIMPLE AND GIVE YOU MULTIPLE TRUE ANSWERS
UNLESS YOU ALREADY UNDERSTAND THE TRICKY PART OF THE QUESTION, PLUG SHIT IN
edit:
The eggs in a contain basket are either white or brown. If the ratio of the number of white eggs to the number of brown eggs is 2/3, each of the following could be the number f eggs in the basket EXCEPT
A. 10
B. 12
C. 15
D. 30
E. 60
answer is B because the number of eggs is a multiple of 5 (because the ratio 2:3)
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Oh, I did not think it like that. Thanks
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EPT
