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edjones answered: 7568 problems
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1 solutions
Answer 254241 by edjones(7569)   on 2010-10-14 00:32:09 (Show Source):
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Probability-and-statistics/356140: two out of three females under the age of 25 have used hair coloring. If a random sample of 15 females under the age of 25 is drawn, find the probability that 10 have used hair-coloring products.
1 solutions
Answer 254236 by edjones(7569) on 2010-10-14 00:16:11 (Show Source):
You can put this solution on YOUR website!(x+y)^15 Let x=2/3 and y=1/3
nCr=15C10=3003
3003*x^10*y^5=.2143 Probability EXACTLY 10 out of 15 have used hair-coloring products.
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Ed
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test/356161: K= 2b + 5c; solve b then solve c. I am very rusty in algebra. My son and I are getting different answers and he doesn't have his book so I can refresh my memory. Can you work this out so we can get and example to finish the others? Thank you.
1 solutions
Answer 254233 by edjones(7569) on 2010-10-14 00:02:07 (Show Source):
You can put this solution on YOUR website!k=2b+5c
.
solve for b.
k-2b=5c
-2b=5c-k
b=(5c-k)/-2
b=-(5c-k)/2
b=(k-5c)/2
.
solve for c.
k-5c=2b
-5c=2b-k
c=(2b-k)/-5
c=-(2b-k)/5
c=(k-2b)/5
.
Ed
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Probability-and-statistics/356147: 65% of the students in a certain small college’s population are women. It is also noted at this college that women are twice as likely to take Poetry as men. In one semester 30% of the college’s women take Poetry. If a randomly selected college student is in a Poetry class, what is the probability that this student is a female?
1 solutions
Answer 254230 by edjones(7569) on 2010-10-13 23:51:12 (Show Source):
You can put this solution on YOUR website!.65 F & .35 M Students
.30 F & .15 M take poetry
.
.65*.30=.195 F taking poetry
.30*.15=.0525 M taking poetry
.
.195+.0525=.2475 student body taking poetry.
.
.195/.2475=.7879 probability student is female.
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Ed
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Probability-and-statistics/356122: Suppose that 4% of all adults over 40 have diabetes. A certain physician correctly diagnoses 95% of all adults over 40 with diabetes as having the disease and incorrectly diagnoses 3% of all adults over 40 without diabetes as having the
disease.
8) Draw a tree diagram and label it with appropriate probabilities.
9) Find the probability that a randomly-selected adult over 40 is diagnosed as not having diabetes.
10) Find the probability that a randomly-selected adult over 40 actually has diabetes, given that he/she is diagnosed as not having diabetes.
1 solutions
Answer 254221 by edjones(7569) on 2010-10-13 23:16:33 (Show Source):
You can put this solution on YOUR website!Note: I rounded all calculations to 3 decimal places.
.95*.04=.038 of population correctly diagnosed as diabetic.
.03*.96=.029 of pop. incorrectly diagnosed as diabetic.
.
9)
1-.038-.029=.933 probability that a randomly-selected adult over 40 is diagnosed as not having diabetes by this physician.
.
10)
.002/(.931+.002)=.002/.933=.002 probability that a randomly-selected adult over 40 actually has diabetes, given that he/she is diagnosed as not having diabetes.
.
Ed
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Functions/356096: Please help! I don't understand this problem at all.
Find the domain of the function f(x) = 3 + √(36-x^2 )/x^2- 9
Please show all work
Thank you!
1 solutions
Answer 254183 by edjones(7569) on 2010-10-13 21:44:12 (Show Source):
You can put this solution on YOUR website!f(x) = (3 + sqrt(36-x^2 ))/(x^2- 9)
.
The denominator cannot equal zero.
x^2-9=(x+3)(x-3)
(x+3)(x-3)=0
x=3, x=-3
So x cannot equal -3 or 3.
The domain of x is all real numbers except -3 and 3.
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Ed
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Linear_Equations_And_Systems_Word_Problems/356094: John is the place kicker for his college football team. Last season he kicked 38 times and never missed. Each field goal scored 3 points and each point after touchdown scored 1 point. If he scored a total of 70 points, how many field goals did John kick last season?
1 solutions
Answer 254181 by edjones(7569) on 2010-10-13 21:32:37 (Show Source):
You can put this solution on YOUR website!Let f=number of field goals and a=number of points after.
a+f=38
a+3f=70
.
a+3f=70
a+ f=38
-------subtract
2f=32
.
f=16 field goals he kicked last season.
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Ed
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test/356098: 1<2A-5<13
(A+4)(A-4)
(A-7)(3A-4)
(3A-7)(2A-9)
A^2-81
A^2-4-21
2A^2-11A+12
|A+2|=9
|A-7|=15
1 solutions
Answer 254176 by edjones(7569) on 2010-10-13 21:18:27 (Show Source):
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Probability-and-statistics/356004: Rework problem 15 from section 3.5 of your text involving a true-false test. Assume that 20 questions are answered by guessing.
What is the probability of exactly 15 correct answers?
1 solutions
Answer 254169 by edjones(7569) on 2010-10-13 20:58:59 (Show Source):
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Travel_Word_Problems/356014: Silvano traveled to the lake and back. On the trip there he traveled 80 km/h and on the return trip he went 60 km/h. How long did the trip there take if the return trip took 4 hours?
1 solutions
Answer 254164 by edjones(7569) on 2010-10-13 20:49:39 (Show Source):
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Functions/356045: 10x+3y+2=9x+8
how do you write the equation in a function form? y=? i need help now this is my homework!please help!
1 solutions
Answer 254140 by edjones(7569) on 2010-10-13 20:02:18 (Show Source):
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Probability-and-statistics/355590: A vacationer has brought along four novels and
four nonfiction books. One day the person
selects two at random to take to the beach.
What is the probability that both are novels?
1 solutions
Answer 253938 by edjones(7569) on 2010-10-13 01:19:55 (Show Source):
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Probability-and-statistics/355591: A student studying for a vocabulary test knows the meanings of 14 words from a list of 20 words. If the test contains 10 words from the study list, what is the probability that at least 8 of the words on the test are words that the student knows? (Round your answer to three decimal places.)
1 solutions
Answer 253937 by edjones(7569) on 2010-10-13 01:13:50 (Show Source):
You can put this solution on YOUR website!14/20=7/10=.7
Let x=.7 and y=.3
(x+y)^10
=x^10+10x^9y+45x^8y2
=.383 probability that at least 8 of the words on the test are words that the student knows.
.
Ed
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Proportions/355621: This is a word problem. I tried to use the formula for inverse variation, y=k/x but I am still not getting the correct answer and I think it is because I do not know how to plug the #s in correctly.
Question: The length of time that a given # of bushels of corn will last when feeding cattle varies inversely with the # of animals. If x bushels will feed 25 cows for 10 days, how long will the feed last for 10 cows?
I know the answer is 25 days, I just do not know how to get it.
Thanks!
1 solutions
Answer 253934 by edjones(7569) on 2010-10-13 00:55:34 (Show Source):
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Graphs/355614: Determine the equation of the line that passes through the points of intersection of the quadratic function f(x) = x^2 - 4 and G(x) = -3x^2 +2x +8
1 solutions
Answer 253930 by edjones(7569) on 2010-10-13 00:45:50 (Show Source):
You can put this solution on YOUR website!We let the equations y coordinates be equal.
x^2-4=-3x^2+2x+8
-4x^2+2x+12=0
x=-1.5, x=2 Quadratic formula.
To find the y coordinate we can use either of the original equations.
x^2-4
=(-1.5)^2-4
=2.25-4
=-1.75
.
2^2-4=0
.
(-1.5, -1.75), (2, 0) the 2 points of intersection.
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Ed
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