I feel like an idiot?

Question

I'm trying to study for my SAT, and i have a lot of trouble in math and none in my other subjects. But i can't even figure out the stupid things when they are explained to me. Can someone please explain in nice dumba** terms for me how to solve these. I think i've forgotten the easy stuff i learned in middle school.

How doyou figure out the answer for "2/3 greater than 3?" (These are parts of the ones i'm having trouble with.

Also how do you figure out 20% of 100, i realize that it's 20 because that's a simple number but i don't remember the mathematical process to figure out the number if it's more difficult.

Thankyou so much, i'm getting so frustrated with my own stupidity.

Here are the questions that these questions came from. My book says to subistitute in easy numbers to solve.

1) In a certain Orchestra, each musician plays one instrument. If 1/5 of the musicians play brass instruments and the number of musicians playing wind instruments is 2/3 greater than the # of musicians playing brass instruments, what fraction of musicians play neither brass nor wind instruments.

2)An Antique dealer usually charges 20% more than his purchase price for any vase sold in his store. During a clearance sale, all items are marked 10% off. If the dealer sells a vase during the clearance slae, his profit on the vase, is what percentage of the purchase price? (The books says to sub in 100 $ for the purchase price of the vase)

Answer 1

How do you figure out the answer for "2/3 greater than 3?" (These are parts of the ones i'm having trouble with.
2/3 * 3=2 so 2/3 greater than 3 is 3+2=5

Also how do you figure out 20% of 100, i realize that it's 20 because that's a simple number but i don't remember the mathematical process to figure out the number if it's more difficult.
% means divided by 100 so 20%=20/100.
20/100 * 100=20



Here are the questions that these questions came from. My book says to subistitute in easy numbers to solve.

1) In a certain Orchestra, each musician plays one instrument. If 1/5 of the musicians play brass instruments and the number of musicians playing wind instruments is 2/3 greater than the # of musicians playing brass instruments, what fraction of musicians play neither brass nor wind instruments.

let x =number of musicians
x/5=b
w=b 2/3 b=5b/3
b=.2x
w=5b/3=5*.2/3 x=1/3x
left are (x-x/5-x/3)=(15x-3x-5x)/15=7x/15
7/15 of the musicians play something other than brass or woodwinds.

2)An Antique dealer usually charges 20% more than his purchase price for any vase sold in his store. During a clearance sale, all items are marked 10% off. If the dealer sells a vase during the clearance slae, his profit on the vase, is what percentage of the purchase price? (The books says to sub in 100 $ for the purchase price of the vase)

lets say he bought the vase for x dollars & listed it for 20% more so he marks it 1.2x. during clearance he marks it down 10%. 10% off of 1.2x=x(1.2-.12)=1.08x. his profit is 1.08x-x=.08x or .08x/x=.08=8% of the purchase price.

Answer 2

1) In a certain Orchestra, each musician plays one instrument. If 1/5 of the musicians play brass instruments and the number of musicians playing wind instruments is 2/3 greater than the # of musicians playing brass instruments, what fraction of musicians play neither brass nor wind instruments.

p(b) = probability of student playing brass
p(w) = probability of student playing wind
p(o) = probability of student playing neither wind nor brass

Given

p(b) = 1/5
p(w) = (1 + 2/3)p(b) = (5/3)p(b) = (5/3)(1/5) = 1/3

p(o) = 1 - p(b) - p(w) = 1 - 1/5 - 1/3 = 7/15

Answer 3

These are very simple questions (to me anyway). I could give you an answer but : Give a man a fish and feed him for one day, Teach a man to fish and feed him for life.

Visualize 100 bottons. Now seperate 20 buttons from the group, you have 20 buttons or 20 percent.

50 buttons. The number has halfed. hence 10 buttons is 20%

200 buttons. The number has doubled. hence 40 buttons is 20 percent

a formula to remember determinant (or 20 buttons) / group (or 100 buttons) * 100 = %

Answer 4

For percents it helps to tihnk of them as proportions. Here's a good website that explains it...
http://amby.com/educate/math/4-2_prop.html
For SAT it's a little different from a test for school because
1) you're operating under stricter time constraints and
2) you have multiple choice answers.
So generally your strategy is to do as much as you can, of what you can do, and don't waste time getting bogged down on the harder stuff. You can make a fairly high score on this strategy, the really hard questions are just tiebreakers so to speak.
Also, go easy on yourself. Beating yourself up will only make your subconsciuos rebel, and then it will be even harder.
There are sites online to help you understand math, some are even interactive. For a tutorial on any subject just put tutorial (subject) in your search window. For example tutorial fractions or tutorial proportions. You can probalby even find SAT preparation tutorials online.
For example
http://www.petersons.com/testprep/default.asp?id=877&path=ug.pft.sat&WT.srch=2&WT.mc_id=92&WT.mc_r=180
(I think that's a commercial site but others are free for example...)
http://www.gomath.com/test/tutorial/body.html
http://www.satmathpro.com/Index.html
I can't see the details of your question from here so I can't go into details on how to solve specific problems, but hopefully this will be enough to get you headed in the right direction.
Good luck on your SAT!

Answer 5

well u are an idiot, 2/3 of 3 is 2, just multiply by the numerator, which comes out to 6/3=2. 20%/100%=20.No real process just put it over 100%