Wednesday, February 18, 2015

The Ends Justify the Means


Psst, I'll tell you a big secret not too many people know: you can solve a question completely incorrectly and still earn full credit if you bubble in the correct answer.

With the exception of the essay, the SAT is graded by a machine. Meaning that no matter what method you use for finding the correct answer, it doesn't matter if you solve the question correctly (or incorrectly). You can solve a graph problem by drawing out the function yourself or plug it in your graphing calculator, and if you get the answer correctly, everything is fine.

Before you get any crazy ideas, I did say (or wrote) that the ends justifies the means, but that doesn't mean you can cheat. What I am trying to tell you that do anything (legal) that it takes for you to answer that extra problem correctly.

Lady, gentleman, or other, I present you an SAT Math question from the Princeton Review.


The Princeton Review

The answer to this problem is (C). You can tell that the clover (shaded region) is about half the area of the square (400 units), so we can tell that the answer has to be around 200. Therefore the answer is (C). I have a post that covers this question in more detail. Here's the link.

Now, embrace yourself for a really math heavy alternative for finding the answer to the problem.

By Integration
By the courtesy of Integration, a YouTuber that posts helpful content for high school and college students (I recommend that you check out his channel), we have here is the Calculus alternative to the question.

If you don't understand what is shown in the image, don't worry. You don't need any of that for the SAT. I don't know any Calculus and I still scored perfectly on the SAT Math. And for those who understand the work written above, you would probably have figured out that setting up functions and using integrals is a waste of time on test day.

So what do you want to do? Use Calculus and waste a lot of time, or estimate the area and get the answer in less than a minute?

It doesn't even have to be Calculus. Here's a sequence problem:

SAT Tutors

You can find the answer by manually writing out the numbers increasing by 3: 

6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48

Spelling out each number is a valid way to solve the question, but it won't be a good choice when you are looking for big numbers such as 100th term or 1000th term. So you might want to use a more "universal" approach.

There is the nth value for an arithmetic sequence formula you can use:

SAT Tutors

OR

Your brain will suffice. 

Start with 6, our first number. Since we are looking for the 15th number, there are 14 new numbers, and each new number increases by 3 from the previous number, so multiply 3 by 14, and you get 42. Add that 42 with 6 and you will get (D) 48.



As you can see, there are many ways to solve a problem. So you do what you find comfortable. Remember, it doesn't matter how you solve the question. It's the fact that you got the answer is what's important. 



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