Mathematics - 16 October 2007

a student needs 20% hydrochloric acid for a chemistry experiment how much 3% acid should be mixed with 20ML of 40% acid to get a 20% soluation

2007-10-16 12:28:57 · 2 answers · asked by investing1987 3

Right now Kim is 15 and her father is 39. In how many years Kim's father will be twice as old as Kim.
Please help.

2007-10-16 12:28:40 · 3 answers · asked by vp68 2

2007-10-16 12:22:26 · 2 answers · asked by Anonymous

2007-10-16 12:18:07 · 4 answers · asked by Anonymous

2007-10-16 12:17:01 · 3 answers · asked by Anonymous

2007-10-16 12:16:40 · 1 answers · asked by kodakboi 1

2+5i/4

2007-10-16 12:12:42 · 3 answers · asked by s p 1

2007-10-16 12:08:35 · 15 answers · asked by kodakboi 1

What is the answer to:





-ix
e





?

2007-10-16 12:05:57 · 2 answers · asked by kramellou 2

itsfor homework please help

2007-10-16 11:57:14 · 6 answers · asked by m 2

six people are going to sit in a row on a bench. Romeo wants to sit next to Juliet. Caesar does not want tosit next to Brutus. Homer and Pierre can sit anywhere. How many ways can these six people be seated?

If the length of the hour and the minute hands of a clock are 4 cm and 6 cm, respectively, what is the distance in cm between the tips of the hands at two o'clock?

Can you answer these?

2007-10-16 11:56:44 · 2 answers · asked by Anonymous

This is the problem,

-2 over 3 + 6 and one eigth.

I cannot figure this problem out.

Also....

-3 and two fifths - five sixths????

I do not understand these problems, any help is appreciated.

2007-10-16 11:54:19 · 15 answers · asked by Anonymous

what equations/stuff do you have to do to prove it is a right angle triangle?

thanks

2007-10-16 11:51:31 · 9 answers · asked by Anonymous

2007-10-16 11:45:11 · 7 answers · asked by twinkle 1

Which of the following is the greatest integer less than 350,000 that can be written using all of the digits from 2 to 7?

349,000

376,542

346,752

347,652

324,765

2007-10-16 11:37:30 · 3 answers · asked by Anonymous

Here is the picture
http://i40.photobucket.com/albums/e215/xxs3xp1stolxx/11.jpg

the book says to use 3.14 for pi, cause you help me find what is the area of the shaded reigion.

Thanks!

2007-10-16 11:35:50 · 3 answers · asked by Marcela M 1

I need to know 2 prime numbers of 18, please.

2007-10-16 11:33:25 · 7 answers · asked by Brandy C 2

I asked this question before but I think it was unclear.
I mean show how like this, a case I understand:

i*√9 = √(-1)*√9 = √((-1)*9) = √(-9)

Start from the left, and go to get the result on the right. Here's my attempt, following the above:

i*√(9*i) = √(-1)*√(9*i) = √((-1)*(9*i)) = √(-9*i)

But this is wrong, somehow I should end up with -√(-9*i) but I don't see how. What is the missing step. Thanks.

2007-10-16 11:15:30 · 4 answers · asked by Nierika 2

is have this equation:
(-2x^3 + 7x^2 + 22x - 48) / (2x^2 - 4x - 16)

in order to find the horiz. asymptote, you need the dominant terms in the numerator and denominator, right?
so wouldnt they be -2x^3 and 2x^2??? is this right?
what are the horizontal asymptotes? are there any??

2007-10-16 11:13:43 · 3 answers · asked by Anonymous

how would i sketch the curve y=2x² - 12x + 23
how would i find the points

plzz help mee...im confused!

tanx

2007-10-16 11:12:33 · 8 answers · asked by -x-lollie-x- 1

A soda glass has the shape of the surface generated by revolving the graph of y=6 x^2 on [0,1] about the y-axis. Soda is extracted from the glass through a straw at the rate of 1/2 cubic inch per second. How fast is the soda level in the glass dropping when the level is 3 inches? (Answer should be implicitly in units of inches per second. Do not put units in your answer. Also your answer should be positive, since we are asking for the rate at which the level DROPS rather than rises.)

if you could talk me through it or give me hints about it that'd be great. the thing that really throws me off is where it says it has the "shape of the surface"..?????

2007-10-16 11:09:50 · 2 answers · asked by arsenic sauce 6

Suppose that a population of adults is surveyed to number the measure the number of hours per week spent on home computers. In the survery, the number of hours is normally distibuted with a mean of 7 hours and a standard deviation of 1 hour.

Find the % of adults that spend more than 4.9 hours on a home computer per week.

If 150 adults are randomley selected, about how many would you expect to say they spen less than 5.4 hours per week on a home computer?

2007-10-16 11:06:15 · 1 answers · asked by deanjp 2

the length of certain species of fish are normally distributed with a mean of 10 inches and a standard deviation of 2 inches. Find the percent of the fish that are longer than 11.7. If 225 of the fish are randomley selected, about how many do you expect to be shorter than 7.3 inches.

Q: Fish longer than 11.7

Q: fish shorter than 7.3

2007-10-16 11:01:47 · 1 answers · asked by deanjp 2

my son is in grade 4 and gets confused with whether the word problem is asking him to multiply or divide? What is the best way he can differentiate? Are there any tips or tricks, or tecniques. I am unable to xplain 2 him.

2007-10-16 10:53:08 · 10 answers · asked by Anonymous

A police helicopter is flying north at 100 mph, and at constant altitude .5 miles. Below, a car is traveling west on a hgihway at 75 mph. At the moment the helicopter crosses over the highway, the care is 2 miles east of the helicopter.
a) How fast is the distance between the car and the helicopter changing at the moment the helicopter crosses the highway?
b) Is the distance between the car and helicopter increasing or decreasing at that moment?

2007-10-16 10:51:06 · 1 answers · asked by kaitlyn 1

of the triangle? Is there a formula?

2007-10-16 10:50:48 · 8 answers · asked by Anonymous

You know what I mean...................

I'm sure this this will be a d'oh answer.

2007-10-16 10:47:29 · 9 answers · asked by curious George 2

Do not find the actual sum like 1+2+3+4...+997+998+999
Rather find the sum of the digits appearing in the number.
For example the contribution of 86 is 8+6

2007-10-16 10:37:06 · 6 answers · asked by chaniquana 1

help

2007-10-16 10:25:52 · 9 answers · asked by hunedip22 1

the problem is (I'm stumped!):

The midsegment of a triangle divides two sides of the triangle into two congruent segments. Make a conjecture about the lengths of parallel segments that divide two sides of a triangle into 4 congruent segments.

Thanks in advance!

2007-10-16 10:24:17 · 1 answers · asked by skateme1 2