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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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pluggin in is a good strat for people that aren't too smart
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Cayman Islands24199 Posts
my professor would resent you secretly if you said plug it in instead of substitute
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On April 05 2009 03:15 Ecael wrote:
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.
That was exactly my point.
And the relevance of someone's maths interest is that someone more interested in maths will most likely study maths later and as such he really needs to start think in variables since that is what higher maths is all about and the sooner the better and the small extra time it takes to understand such things is nothing if you are into it.
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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...?
why would it even seem like that? did you read the question? does that seem like a bad way to do it
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remember that the second question is asking for the eggs' ratio in relation to each other, not total number of eggs
so it can't be a, 4 white eggs / 6 brown eggs = 2/3, 4+6 = 10
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On April 05 2009 06:03 Divinek 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...? why would it even seem like that? did you read the question? does that seem like a bad way to do it
Okay, tell me how it's not a better approach to use variables:
There are 75 more women than men enrolled in Linden College. If there are n men enrolled, then in terms of n, what percent of those enrolled are men?
To solve it using variables (which was given ffs):
# of men: n
# of women: n+75
% men = 100 * # men / [(total =) #men + #women]
:. % men = 100 * n / (n + n + 75)
To solve with numbers
You have to derive the exact same expression with 25, and calculate a concrete percentage, then match this percentage with all the wrong ones in the answer. If you don't see why this is more time consuming and redundant, then I guess there is a reason why you think it's a better idea to use numbers. And also, if you know to use 25 (it's not magic btw), you've pretty much got the problem solved. Imagine if you used 1, or 15 even, solve by numbers wouldn't be so easy.
By more error prone, I mean you have to type this number into a calculator multiple times, every time you type it, you are introducing potential errors.
tl;dr version:
Using numbers is the same as using variables except you have to perform the actual calculation.
If you can solve the problem with numbers, how is it possible that you can't do it with variables?!
Question 2:
You are given a ratio of white vs. brown, you have to derive the expression of white vs. total or brown vs. total. You'll see that the total has five "shares", so that the total number of eggs must be a multiple of five.
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On April 05 2009 06:18 Cambium wrote:
tl;dr version:
Using numbers is the same as using variables except you have to perform the actual calculation.
If you can solve the problem with numbers, how is it possible that you can't do it with variables?!
If you know the formulas but can't derive them and don't understand them.
Edit: Also it is a perfect way to check that your answer is actually correct.
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meh I dont like how they try to trick you on those standardized tests, Id have gotten 1 wrong because I didnt multiply by 100, and 2 is just gay 
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On April 05 2009 06:54 Sadist wrote:meh I dont like how they try to trick you on those standardized tests, Id have gotten 1 wrong because I didnt multiply by 100, and 2 is just gay
i don't understand this, especially now the ability to do the type of math that is being tested isn't as much of a benchmark as it is to be able to think accurately about how to solve the problem, but i did well on the sat so i guess i'm biased :O
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Kentor
United States5784 Posts
On April 05 2009 06:54 Sadist wrote:meh I dont like how they try to trick you on those standardized tests, Id have gotten 1 wrong because I didnt multiply by 100, and 2 is just gay
i do. there are plenty of easy questions where there are no tricks. of course there should be some "hard" questions in there too.... can't be all easy.
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On April 05 2009 05:11 lilpwnyIII wrote:
pluggin in is a good strat for people that aren't too smart
You're wrong. Plugging in is in itself faster than working with variables. It isn't a contest for people to prove how smart they are, it is a contest to get it *right*. Being right is all that matters. If plugging in lets you do it faster, then you better do it so when you finish earlier, you have more time to check over your answers.
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On April 05 2009 06:18 Cambium wrote:Show nested quote +On April 05 2009 06:03 Divinek 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...? why would it even seem like that? did you read the question? does that seem like a bad way to do it Okay, tell me how it's not a better approach to use variables: There are 75 more women than men enrolled in Linden College. If there are n men enrolled, then in terms of n, what percent of those enrolled are men? To solve it using variables (which was given ffs): # of men: n # of women: n+75 % men = 100 * # men / [(total =) #men + #women] :. % men = 100 * n / (n + n + 75) To solve with numbers You have to derive the exact same expression with 25, and calculate a concrete percentage, then match this percentage with all the wrong ones in the answer. If you don't see why this is more time consuming and redundant, then I guess there is a reason why you think it's a better idea to use numbers. And also, if you know to use 25 (it's not magic btw), you've pretty much got the problem solved. Imagine if you used 1, or 15 even, solve by numbers wouldn't be so easy. By more error prone, I mean you have to type this number into a calculator multiple times, every time you type it, you are introducing potential errors. tl;dr version: Using numbers is the same as using variables except you have to perform the actual calculation.If you can solve the problem with numbers, how is it possible that you can't do it with variables?! Question 2: You are given a ratio of white vs. brown, you have to derive the expression of white vs. total or brown vs. total. You'll see that the total has five "shares", so that the total number of eggs must be a multiple of five.
Of course solving with variables is great if you actually know the maths to do it right. But, seeing as he is actually asking these questions; he probably isn't all that comfortable with working with variables, and besides, it is easy to mess something up and get one of their intentionally-almost-correct answers. Solving with actual numbers is actually pretty damn good for these reasons.
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On April 05 2009 08:02 Archaic wrote:Show nested quote +On April 05 2009 05:11 lilpwnyIII wrote:
pluggin in is a good strat for people that aren't too smart You're wrong. Plugging in is in itself faster than working with variables. It isn't a contest for people to prove how smart they are, it is a contest to get it *right*. Being right is all that matters. If plugging in lets you do it faster, then you better do it so when you finish earlier, you have more time to check over your answers.
Actually, since people in more advance math usually work with concepts and abstractions instead of concrete variables, they are used to working with variables and thus the plugging in method is faster for them. But it all depends on what you're comfortable with; the way you solve a SAT Math problem does not dictate your knowledge.
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E
(total = n + n + 75)
B
(total is multiple of 2+3 = 5)
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I can't do these without pencil and paper...god I feel dumb.
I'm a philo major...my math requirement was an intro computer class where I learned how to use Word and Excel...lawl.
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On April 05 2009 08:43 Avidkeystamper wrote:Show nested quote +On April 05 2009 08:02 Archaic wrote:On April 05 2009 05:11 lilpwnyIII wrote:
pluggin in is a good strat for people that aren't too smart You're wrong. Plugging in is in itself faster than working with variables. It isn't a contest for people to prove how smart they are, it is a contest to get it *right*. Being right is all that matters. If plugging in lets you do it faster, then you better do it so when you finish earlier, you have more time to check over your answers. Actually, since people in more advance math usually work with concepts and abstractions instead of concrete variables, they are used to working with variables and thus the plugging in method is faster for them. But it all depends on what you're comfortable with; the way you solve a SAT Math problem does not dictate your knowledge.
I hope you meant that using variables is faster if you are experienced with maths, thing is that you can see the answer to the question instantly if you are and thus it is impossible to do it faster by plugging in random numbers...
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I got a physics/engineering degree and I still don't know my multiplication tables. Thats what happens when you never plug anything in...
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At least for this men and women question, it should be solvable by variables in just a few seconds...
I guess I can see the substitution option coming in handy to check or something, but I've been educated to work it out algebraically pretty much all the time >_>
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Wait no one is bragging how they are right and how their sat score raped your mom you get a discusting amount of time for the sat's if you konw what your doing you have more then enough time to plug shit in.
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On April 05 2009 12:00 IzzyCraft wrote:
Wait no one is bragging how they are right and how their sat score raped your mom you get a discusting amount of time for the sat's if you konw what your doing you have more then enough time to plug shit in.
i pretty much agree here, if you have enough time to, absolutely plug and chug the answers, what's the downside? if it catches one mistake and doesn't waste time it's worth it, my advice is to finish the test in whatever fashion you normally would and if you have time go back and check the answers manually
wait until the GREs where you don't have a calculator \o/
(ps the gre math is easier anyway so no worries)
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On April 05 2009 15:10 Wasabi wrote:
(Since someone has already mentioned the answers for the SAT questions I don't feel like answering it myself, although I used a method that isn't subsitution)
I'm not a practitioner of plug and chug. Using the plug and chug method means you probably don't understand the problem from the root up. If you try to apply this OUTSIDE a multiple choice question, such as in lab work where you may not be given a formula to plug numbers into, you'll be dumbfounded figuring out the formula yourself since you're so used to subsitution. Your ability to think critically is hampered with substitution. Getting accostumed to use false, presumptuous numbers isn't the way to go for finding real solutions. You don't go and jump to a solution in many things that you'll do in college. Though there are shortcuts to pretty much anything, many of them definitely don't involve trial and error.
yeah my english major had a lot of lab work, damn you plug and chug!
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On the SAT however, plug and chug (especially after eliminating the impossible answer choices) is much faster then most methods. Regardless if you know the concept or not, doing it will probably get you a higher score, and that's all that matters on the SAT >.<.
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On April 05 2009 02:08 il0seonpurpose wrote:Edit: Here's another question I don't get 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 + Show Spoiler +
So I put A for obvious reasons, you can't divide 10 evenly with 3 and so you'd had like a third or two thirds of an egg. But in the answer key, it says it's A! Help please
Yeah the wording in the SAT can be a little tricky. When I first read this, I thought 2/3 of the eggs are white, which is what you probably thought as well. Watch out for the word "ratio." I try to think about it as "2:3" rather than "2/3" because I tend to associate the latter with fractions.
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EPT
