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Mathematics 18 Online
OpenStudy (anonymous):

zarkon , I need help Please!

OpenStudy (anonymous):

Maybe you should just ask your question and hope someone can answer.

OpenStudy (anonymous):

Janice has 8 DVD cases on a shelf, one for each season of her favorite TV show. Her brother accidentally knocks them off the shelf onto the floor. When her brother puts them back on the shelf, he does not pay attention to the season numbers and puts the cases back on the shelf randomly. Find each probability. 1. P(all even-numbered seasons followed by all odd-numbered seasons) 2. P(all even-numbered seasons in the correct position) 3. P(seasons 5 through 8 in any order followed by seasons 1 through 4 in any order)

OpenStudy (anonymous):

maybe if i write it with words it will be more clear, because i guess it didn't work the first time. sometimes words escape me. lets do the first one slow. all even numbers followed by all odd numbers. first one is even, 4 out of 8 or 4/8 second one is even given that first one is even is 3/7 since there are thee even and 7 to choose from third one is even given first two are is 2/6 and finally fourth one is even is 1/5 now you are done, because if all the even ones are first necessarily all odds will be second. so your answer is \[\frac{4}{8}\times \frac{3}{7}\times \frac{2}{6}\times \frac{1}{5}\]

OpenStudy (anonymous):

1)? the key is: 1/8!

OpenStudy (anonymous):

really??

OpenStudy (anonymous):

funny because i saw that answer elsewhere and assumed it was wrong. there are 8! ways to arrange these dvds yes?

OpenStudy (anonymous):

so to say the answer is \[\frac{1}{8!}\] means there is only one way to do this. but that is silly

OpenStudy (anonymous):

I don't need number 2, how about 3 ) ?

OpenStudy (anonymous):

3) should be the same.

OpenStudy (anonymous):

1) and 3) the same?

OpenStudy (anonymous):

just replace the word "even" by 5 through 8 and the word "odd" by 1 through 4

OpenStudy (anonymous):

there are 4 even and there are 4 labeled 5 though 8 etc. these should be the same. i don't understand why it would say the answer to the first one is 1/8!

OpenStudy (anonymous):

maybe i am reading the question wrong

OpenStudy (anonymous):

nope i am sticking with my answer. there is clearly more than one way to do this yes?

OpenStudy (anonymous):

I'm not good at probability

OpenStudy (anonymous):

where is the answer key? is it in the book? on line?

OpenStudy (anonymous):

I disagree Satellite. There is only one way to do this.

OpenStudy (anonymous):

ooh? then i am wrong

OpenStudy (anonymous):

You must pick all the even seasons first, and all the odd seasons second.

OpenStudy (anonymous):

but the way i read it i will give you two 2, 4, 6, 8 4, 2, 6, 8

OpenStudy (anonymous):

2) 4!/8! 3) (4!*4!)/8!

OpenStudy (anonymous):

3) is the same answer i wrote

OpenStudy (anonymous):

From the set of 4 even numbered we will chose 4 disks. There is only 1 way. Then from the set of 4 odd numbered we will chose 4 disks. There is only 1 way for this also. We don't care what order they are in inside.

OpenStudy (anonymous):

For the purposes of this problem, choosing 2,4,6,8 is the same as choosing 4,3,6,8

OpenStudy (anonymous):

\[\frac{4!\times 4!}{8!}=\frac{4!}{8\times 7\times 6\times 5}\] \[=\frac{4}{8}\times \frac{3}{7}\times \frac{2}{6}\times \frac{1}{5}\] they are the same

OpenStudy (anonymous):

That being said. I am also not great at probability.

OpenStudy (anonymous):

ok so we agree that the answer to c) is what you wrote and what i wrote, because they are the same yes?

OpenStudy (anonymous):

I think I get now: denominator is 8! 5 through 8= 5,6,7,8,= 4! 1 through 4=1,2,3,4 = 4! than (4!*4!)/8!

OpenStudy (anonymous):

Hrm. But I'm also feeling like C should have the same answer as A. So I'm probably totally wrong ;p

OpenStudy (anonymous):

@polpak i can demonstrate more than one way to do number 1 and in fact number 1 and number 3 are the same with the words changed from "even" to 1-4 etc

OpenStudy (anonymous):

so i am sticking with my answer.

OpenStudy (anonymous):

you can think of it as \[\frac{4!\times 4!}{8!}\] if you like but i think it is more intuitively clear if i write \[\frac{4}{8}\times \frac{3}{7}\times \frac{2}{6}\times \frac{1}{5}\]

OpenStudy (anonymous):

no number two is different

OpenStudy (anonymous):

1) and 3) = 4!/8! or 3) = (4!*4!)/8!

OpenStudy (anonymous):

I don't need 2)

OpenStudy (anonymous):

number two requires the even numbered ones to be in the correct position, not any positiion

OpenStudy (anonymous):

2) and 3) the same ? 4!/8!

OpenStudy (anonymous):

number two is \[\frac{4!}{8!}=\frac{1}{8}\times \frac{1}{7}\times\frac{1}{6}\times \frac{1}{5}\]

OpenStudy (anonymous):

no one and 3 are the same

OpenStudy (anonymous):

any order. just separated

OpenStudy (anonymous):

how 3 )?

OpenStudy (anonymous):

one and three are \[\frac{4!\times 4!}{8!}\]

OpenStudy (anonymous):

1. P(all even-numbered seasons followed by all odd-numbered seasons) 3. P(seasons 5 through 8 in any order followed by seasons 1 through 4 in any order) the way i read these they are identical

OpenStudy (anonymous):

there is no order given for the first one the second one say "any order" explicitly. so just replace the word "even-numbered" by the words "season 5 through 8" and they are the same

OpenStudy (anonymous):

thank, I'm very bad at probability, I better with geometry.

OpenStudy (anonymous):

good luck

OpenStudy (anonymous):

here is a site with the answer you had for the first one, but i am sure it is wrong. http://www.algebra.com/algebra/homework/logarithm/logarithm.faq.question.473393.html it says "# of ways to pick 4 even: 1" but that is not correct. you can pick 2, 4, 6 8 4 ,2 6, 8, 2, 4, 8, 6 etc. there are 4! ways to do it, not one

OpenStudy (zarkon):

#1) has to be \[\frac{4!\cdot4!}{8!}\]

OpenStudy (anonymous):

bless you.

OpenStudy (zarkon):

;)

OpenStudy (anonymous):

i was thinking very simply. don't know if you read my post. i explained it in words

OpenStudy (anonymous):

maybe if i write it with words it will be more clear, because i guess it didn't work the first time. sometimes words escape me. lets do the first one slow. all even numbers followed by all odd numbers. first one is even, 4 out of 8 or 4/8 second one is even given that first one is even is 3/7 since there are thee even and 7 to choose from third one is even given first two are is 2/6 and finally fourth one is even is 1/5 now you are done, because if all the even ones are first necessarily all odds will be second. so your answer is

OpenStudy (zarkon):

if they wanted all even (in order) then all odd (in order ) then we would have \[\frac{1}{8!}\]

OpenStudy (anonymous):

\[\frac{4}{8}\times \frac{3}{7}\times \frac{2}{6}\times \frac{1}{5}\]

OpenStudy (zarkon):

yep

OpenStudy (anonymous):

3)?

OpenStudy (anonymous):

i thought i was losing my mind because this looked fairly straight forward but "answer key" said 1/8! which is silly so did web post i found

OpenStudy (zarkon):

same as #1

OpenStudy (anonymous):

bless you again. just change the words

OpenStudy (zarkon):

1/8! is clearly wrong

OpenStudy (anonymous):

2) 4!/8! ?

OpenStudy (anonymous):

right. that would mean there is only one way to do it. do not trust everything you read on the web. especially here!

OpenStudy (zarkon):

yes

OpenStudy (anonymous):

bless you again. but i would write it as \[\frac{1}{8}\times \frac{1}{7}\times \frac{1}{6}\times \frac{1}{5}\]

OpenStudy (anonymous):

by reasoning it out, rather than some formula

OpenStudy (anonymous):

in fact though it is clearly correct i think it rather silly to write \[\frac{4!}{8!}\]

OpenStudy (anonymous):

I hate do probability, I rather take geometry instate

OpenStudy (zarkon):

how about \[\frac{1}{8}\cdot\frac{1}{7}\cdot\frac{1}{6}\cdot\frac{1}{5}\] I prefer \cdot ;)

OpenStudy (anonymous):

ooh nifty

OpenStudy (anonymous):

cdot has one few letter than times too!

OpenStudy (zarkon):

you can also have \[\cdots\] \cdots

OpenStudy (anonymous):

we need latex forum tricks and tips maybe a wolram one too

OpenStudy (zarkon):

\[\ddots\] \[\vdots\]

OpenStudy (anonymous):

now you are showing off. give...

OpenStudy (zarkon):

lol

OpenStudy (anonymous):

Josh types the five entries in the bibliography of his term paper in random order , forgetting that thet should be in alphabetical oder by author ,What is the probability that he actually typed them in a alphabetical order?

OpenStudy (anonymous):

1/5!

OpenStudy (anonymous):

only one way to type in alphabetical order, 5! ways to arrange them

OpenStudy (zarkon):

\[\checkmark\]

OpenStudy (anonymous):

\[\check\]

OpenStudy (anonymous):

no i guess not

OpenStudy (zarkon):

\checkmark

OpenStudy (anonymous):

sorry I post wrong one, this one The game of euchre (YOO ker) is played using only the 9s, 10s, jacks, queens, kings, and aces from a standard deck of cards. Find the probability of being dealt a 5-card hand containing all four suits.

OpenStudy (anonymous):

\[\checkmark\]

OpenStudy (anonymous):

\[\vdots\]

OpenStudy (zarkon):

\[\clubsuit\diamondsuit\heartsuit\spadesuit\]

OpenStudy (anonymous):

wow how you post the suite?

OpenStudy (zarkon):

\clubsuit\diamondsuit\heartsuit\spadesuit

OpenStudy (anonymous):

i got \[\clubsuit\diamondsuit\heartsuit\spadesuit\]

OpenStudy (anonymous):

ok i am off let me know if you get the same answer i got. i think it was \[\frac{6^4\cdot 5\cdot4\cdot3\cdot2}{24\times 23\times 22\times 21\times 20}\]

OpenStudy (zarkon):

hmm..I'm not getting that

OpenStudy (anonymous):

I may skip this question, thank all your guy

OpenStudy (anonymous):

how about this Describe an event that has probability of 0 and an event that has probability of 1. probability made me headache

OpenStudy (zarkon):

roll a 6-sided die...what is the probability you get a 0 flip a coin...what is the probability you will get a head or tail

OpenStudy (anonymous):

roll=1/6 flip a coin=1/2

OpenStudy (zarkon):

P(get a 0)=0 P(H or T)=1

OpenStudy (anonymous):

are you still around , I will post some more probability later , I run some errant and be back later. Thanks

OpenStudy (zarkon):

here is my answer to your previous problem...

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