Science & Mathematics - 14 January 2007

Q: A total of $12,000 is invested in two corporate bonds that pay 7.5% and 9% simple interest. The investor wants an annual interest income of $990 from the investments. What is the most that can be invested in the 7.5% bond?

Would the equations be
12,000 = 9x + 7.5y
and
990 = x + y ? Is this right?

Also, what exactly is interest and investment?

2007-01-14 18:17:02 · 2 answers · asked by Anonymous in Mathematics

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What websites or other avenues can I go through to get info on: Zeta Reticuli & Theta Draconis?

2007-01-14 18:15:46 · 2 answers · asked by sunshaun 2 in Astronomy & Space

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If u r walking in a circular walking track clockwise and ur friend is walking anti clockwise, find out ratio?

of the speeds of both of u, if u both across by each other
a) 2 times in a complete round.
b) 3 times in a complete round.

2007-01-14 18:12:22 · 3 answers · asked by Ishfaq A 3 in Physics

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Neutralization Question?

I wanted to add 150 mL of 18 M H2SO4 to my drain to clean it, but instead I spilled it on the floor. How much baking soda (grams of NaHCO3) do I need to pour on it to neutralize it?

H2SO4 + 2 NaHCO3 ---> Na2SO4 + 2 H2CO3

2007-01-14 18:09:35 · 4 answers · asked by justinz_1fan 2 in Chemistry

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Non digital, traditional watch, how many times its minutes hand comes exactly over hours hand and after how?

much time each time?

2007-01-14 18:04:23 · 6 answers · asked by Ishfaq A 3 in Mathematics

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find the equation of the tangent to the curve y=2x^2+3x that is parallel to the line y=14x-6?

its kind of hard, since i have only learned how to work with a point, havent learn the prallel or perpendicular part.
Find the equation of the tangent to the curve y=2x^2+3x that is parallel to the line y=14x-6? this question really beats me. SOME1 Help!!!

2007-01-14 18:03:27 · 2 answers · asked by Anonymous in Mathematics

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Quadratic Equation Word Problem?

A playground 40 meters wide by 60 meters long is to be doubled in area by extending each side an equal amount. By how much should each side be extended?

I thought I had this one in the bag, but the answer didn't check!
My equation was: (2x+60)(2x+40)=4800 but the answer I cam up with didn't check! Please help!

2007-01-14 18:01:24 · 7 answers · asked by Audy 1 in Mathematics

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When is hurricane season in Florida USA?

2007-01-14 17:57:07 · 2 answers · asked by Philip J 1 in Weather

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Distance = Rate*Time Word Problem?

In how many minutes after 5 o'clock will the hands of a clock first be together?

I have no idea how to set up an equation for this word problem except maybe x/12 for the hour hand. Please help!

2007-01-14 17:53:07 · 9 answers · asked by Audy 1 in Mathematics

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a) why are the results from this survey more reliable than one person's observation?

In january 2002, thousands of pupils recorded the numbers of different birds seen in their gardens in one hour. they sent their data to the Royal Society for the Protection of Birds who have kept data for many years.

pupils observed birds in their gardens for one hour during the last week in january.

which two factors are being controlled in this survey?

2007-01-14 17:51:37 · 6 answers · asked by pammy 1 in Zoology

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which matrices has all their eigenvalues as real numbers?

2007-01-14 17:45:44 · 2 answers · asked by farzan 1 in Mathematics

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Prove x+y+z <= x^2+y^2+z^2 where?

where

x, y, z all > 0
and
xyz =1

I've done similar problems in the past. I know that I can shift everthing to one side and put in a factored form:

0 <= (x-1/2)^2+(y-1/2)^2+(z-1/2)^2 -3/4

but where to go from here, or even what to do.

Looking at the conditions, since x,y, and z > 0 then we can express
x=1/(yz)

and similar with y, z...

Any ideas?

2007-01-14 17:42:50 · 5 answers · asked by modulo_function 7 in Mathematics

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Any tips of solving the word problems?

I always have trouble solving word problems. It's not as though I'm terrible in English, but I just happen to do not so well since I'm overwhelmed and panicking during the test.

Could you give me an advice in solving word problems? How do you know what they are asking, which information given you use, etc.

2007-01-14 17:41:26 · 6 answers · asked by Anonymous in Mathematics

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is it necessary for the last few rows of a matrix to be zeros in order to find its rank in echelons form?

2007-01-14 17:39:39 · 1 answers · asked by sandra 1 in Mathematics

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can anyone figure this series out?

Consrider a pyramid constructed of stacked spheres ( ex. a pyramid of oranges). The first layer of the pyramid has only one sphere. The second layer( just beneath the first ) has 3 spheres. The third layer has 1 + 2+ 3 = 6 and the Nth layer has 1 + 2 + 3 +....+ N spheres.
Express the number of spheres in the Nth layer as afunction of X?

2007-01-14 17:36:30 · 4 answers · asked by JO 2 in Mathematics

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can anyone figure this series out?

Consrider a pyramid constructed of stacked spheres ( ex. a pyramid of oranges). The first layer of the pyramid has only one sphere. The second layer( just beneath the first ) has 3 spheres. The third layer has 1 + 2+ 3 = 6 and the Nth layer has 1 + 2 + 3 +....+ N spheres.
Express the number of spheres in the Nth layer as afunction of X?

2007-01-14 17:34:00 · 4 answers · asked by JO 2 in Mathematics

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