so I have the GRE tomorrow & I'm cramming in 12 years of math, help?

[Naomi]

Basically, I waited until Saturday to start studying for the GRE, which is tomorrow. Lol. FML.

Anyway, really the verbal reasoning & writing sections are what really matter for me because I'm applying for a PhD program in English Lit. Howeveeeer, I don't want to make a complete fool of myself in the quantitative reasoning section (and also I feel like nothing I do tonight will help increase my verbal reasoning score, so I might as well focus on math.)

I just completed a practice test, and I have a few questions I couldn't get; it's been 3 years since I took Calc 2 and many more years since I learned this kind of math. I could look them up, but I'm tired & strapped on time. Anyone want to give me thorough and easily understandable explanations for rep? c:

Here goes...


1. Which of the following is equal to (6^14)/[(2^5)(3^7)]? NO CALCULATOR

(2^2)(3^2)
(2^7)(3^7)
(2^9)(3^2)
(2^9)(3^2)
(2^9)(3^9)

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2. A certain experiment has three possible outcomes. The outcomes are mutually exclusive and have probabilities p, p/2, and p/4, respectively. What is the value of p?

(The correct answer is 4/7, I guessed 1/7 and that was wrong, lol. Why?)

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3. A certain identification code is a list of five symbols: S1,S2,D1,D2,D3. Each of the first 2 symbols must be one of the 26 letters of the English alphabet, and each of the last 3 symbols must be one of the 10 digits. (Repeated letters and digits are allowed.) What is the total number of different identification codes.

I miraculously guessed this correctly (knowing that there are 10,000 possible 4-digit pins helped LOL), but I want to know how to figure this out, because this kind of question pops up a lot, and I used to always get them wrong on the SAT too. The correct answer is 676,000.


Thanks guys!!

[Poem]

1. Which of the following is equal to (6^14)/[(2^5)(3^7)]? NO CALCULATOR

(2^2)(3^2)
(2^7)(3^7)
(2^9)(3^2)
(2^9)(3^2)
(2^9)(3^9)

Remember that (a*b)^c = a^c * b^c and (a/b)^c = a^c/b^c

so 6^14 = 2^14 * 3^14
cancel out with the denomiator, so you get 2^9 * 3^7

.... which isn't one of the options? why isn't it an option...





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2. A certain experiment has three possible outcomes. The outcomes are mutually exclusive and have probabilities p, p/2, and p/4, respectively. What is the value of p?

(The correct answer is 4/7, I guessed 1/7 and that was wrong, lol. Why?)

so with these questions you want to find make them into integers so it's easier. multiply them by the same number

you get 4p, 2p, and p. (you can do this because the ratio between them is still the same)

so yeah add them together, you have 7ps right? but remember your original p is now 4p, so it is 4/7

i feel like this is probably not the best way of explaining things. if it makes it easier, don't do the multiplying thing. just add p, p/2 and p/4 & simplify. your p value should be 4/7





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3. A certain identification code is a list of five symbols: S1,S2,D1,D2,D3. Each of the first 2 symbols must be one of the 26 letters of the English alphabet, and each of the last 3 symbols must be one of the 10 digits. (Repeated letters and digits are allowed.) What is the total number of different identification codes.

I miraculously guessed this correctly (knowing that there are 10,000 possible 4-digit pins helped LOL), but I want to know how to figure this out, because this kind of question pops up a lot, and I used to always get them wrong on the SAT too. The correct answer is 676,000.


Just remember with this kinda thing you multiply the possibilities together.
there are 26 possibilites for S1, 26 possiblites for S2, and 10 possiblities each for D1,2, and 3. 26*26*10*10*10 = 676000

[Naomi]

@(you need an account to see links) LOL you're right, I mistyped..
(2^9)(3^2) is supposed to be (2^9)(3^7)

THANK YOU YOU'RE THE BEST, rereading the explanation now to make sure I understand. xD
rep coming your way <3

EDIT: ..omg they're all so easy once you explain them wowow, this makes me so happy thanks for the easy to understand explanations

[Poem]

@(you need an account to see links)
No problem! Hope I helped & good luck!

it was fun doing math that i can actually understand again. i'm currently failing math so this was kind of nice.

[teddy]

GOOD LUCK @(you need an account to see links)! I know you'll ace it <3

[Naomi]

@(you need an account to see links) THANKS SO MUCH
i got my quant/verbal scores back immediately after taking it, and I actually did better than I was anticipating.. should be good enough to get me into the program I'm interested in, woot woot! ....as long as I didn't royally mess up the writing section lol.

[Foxglove]

Congrats on getting better-than-expected scores!
I have to prepare for the GRE too, this was a good reminder that I should start studying xD

[Naomi]

@(you need an account to see links), though I definitely don't recommend waiting as long as I did, it's totally an easy-to-study-for exam.

Even the writing section is pretty straightforward.. I just read some of the score 6 responses, and it seemed they all followed the same sort of formula and used the same kind of verbiage. Unfortunately, the vocab is a bit difficult to study for, but weirdly enough, I chanced across a couple words that HAD actually appeared in my practice tests so maybe they recycle the same words a lot?

GOOD LUCK!! And thank you!