Got Homework?
Connect with other students for help. It's a free community.
Here's the question you clicked on:
 0 viewing
An urn contains 7 white balls and 3 red balls. Three balls are selected. In how many ways can the 3 balls be drawn from the total of 10 balls
a) If 2 balls are red?
b) If 3 balls are red and 2 are white?
c) If at leas 4 are red balls?
 2 years ago
 2 years ago
An urn contains 7 white balls and 3 red balls. Three balls are selected. In how many ways can the 3 balls be drawn from the total of 10 balls a) If 2 balls are red? b) If 3 balls are red and 2 are white? c) If at leas 4 are red balls?
 2 years ago
 2 years ago

This Question is Closed

NodataBest ResponseYou've already chosen the best response.2
I'm trying to understand the problem.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
I suppose I have to use combinations.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
me too are we taking out 3 or more?
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
it says 3 but then talks about if 4 are red...
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
so for the first are we assuming that 2 of the 3 we are taking out are red or...?
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
I guess. But if that is the case then I need to use a permutation.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
that's what I'm confused on if the first question is asking 'we draw 3 balls, how many ways can we do this of two of the three we take out are red?' then I would say 3 ways to select red balls 7 ways to select the white ball 3*7=21 but then what about the rest?
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
that's if the balls are unique of course^
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
No they are not unique.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
oh, well then I'm really confused. I especially don't see how you can have 4 red balls when it says there are 3 in the urn..:/
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
I made a mistake. I copy part of the problem below the one i wanted.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
b) If all 3 balls are white.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
c) If all 3 balls are red=
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
well I still don't get the question. if it is as I said above and the balls are not unique, then...no I'm lost, sorry
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
Well at least I'm don't feel alone with the problem =)
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
I really want to understand this counting techniques.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
lol I'll be interested to see if someone understands it. Buena suerte!
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
I think you were right TuringTest. They can be called: red_1, red_2, red_3, etc.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
In that case I'm selecting 2 out of 7 white balls and 1 out of 3 red balls. So.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
I though the first was 2 red balls and one white
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
does the order that we pull them out in matter? I guess it should, so my above answer is wrong.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
a) If2 balls are white and 1 is red.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
The order matters, otherwise I'm lost.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
yes, otherwise the answer to c) is 1
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
Tu sabes español verdad T
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
well c) should still be the easiest: 3!=6
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
on poco tengo que hacer la tarea para miercoles. no hice nada en lalas vacaciones! estas de acuerdo conmigo acerca parte c) ?
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
Ahh. What do you think about this: I help you with your spanish, and you can help me with my english.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
your english is a lot better than my spanish I'm going to school here taking language classes do you agree about part c?
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
I think the answer to c) is 1
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
only if the order doesn't matter
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
if it does then it is 6 do you want me to convince you?
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
Are you sure the order matters?
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
I'm going to draw some circles to represent the balls lol
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
Well Hero sometimes help with my english. Hi write something to him and he says: "No, you can write that in this way". I'm very grateful to him, but I'm ashamed that I can't not help him with something I know.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
I was wondering if I can ask you similar things, and I can help you if you have spanish doubts.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
Well even if you can't help me, you can always ask me if you have some doubts.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
"can't not help him" should be "can't help him" and I your the first mexican I've met who actually wants to help. All my friends just make fun of me. anyhow I see 6! ways te select 2 white balls out of 7
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
I meant 6+5+4+3+2+1=21 ways to select the two white ones
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
But if the order matters It should be a permutation, so P(7,2) is not equal to 6! I think.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
no, I was wrong about that sorry my working theory is that the order does not matter and that there are 21 ways to select 2 white balls out of seven, and 3 ways to select the red one for each of those, so 21*3=63 ways for part a) make any sense?
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
ok then let's see if I have anything for b)...
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
I thought about selecting 3 whites out of 7, so C(7,3) = 35
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
well so then the answer is a)63 b)35 c)1 IF the order of selection does not matter. so what if it does???
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
Mmm good question, I'm thinking about it.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
I don't think I know how to do those.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
So you think this problem is done?
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
That would be great! hehe
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
I think you probably know better. Where did you get this problem? Does it seem like it should be so difficult as to have to consider order? That seems extraneous to me, unless you have an advanced combinatorics book or something.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
It is from the book: "College Algebra" written by Sullivan. It seems isa High School book.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
Then I think we are done :)
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
Thank you =). And what do you have to do for homework?
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
I'm trying to figure out what my girlfriend just texted me... chulos ojos de perrito enamorado not sure what enamorado means, but it must be enamored, eh? I have to do adverbs, practice past participle, negations, and... I don't know. A lot. I should have done it over break.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
enamorado means to be in love.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
awww well that's almost what enamored means
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
I finished my credits at college, I hope to get my undergraduated grade this year.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
Mechatronics Engineering
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
I don't understand quite well what you mean with enamored. Does that word exist in english?
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
Dang, what math did you have to take for that? I would think a lot, but it seems like you don't know too much more than me.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
enamored means obsessed basically, but the word doesn't mean something quite as bad as obsessed
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
Ahh so you were almost right.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
or 'awestruck' like I'm enamored by the presence of somebody special so almost...
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
well I took the basics matehmatics, Algebra, Linear Algebra, Analytic Geometry, Calculus, Probability(Even it seems I didn't), Differential Equations, Complex Analisys, etc.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
because that's where I want to go
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
and you told me you lived in DF
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
Ohh, want do you want to study there?
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
Whatever the highest physics I can get into is.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
I mispelled something, nevermind. So you want a physic's PhD, at UNAM.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
If I can. I don't know how they feel about gringos getting in though. But UGDL sucks.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
So you are studying at UGDL right now.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
Just two classes. Between that, moving here, and language I'm busy. It's just a bad system in my opinion. They don't have high enough standards.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
You mean academic standars, or administrative standars?
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
academic was what I meant, but I'm sure administrative as well. My girlfriend had 4/6 of her graphic design teachers be about 25 years old. I'm almost that old! Not exactly tenure...
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
Well the teachers here are very old hehe.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
but there is a good academic level too.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
But I think that the best option is at Cinvestav, have you heard of it?
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
It's has several (places?) on the country, Queretaro, D.F, I'm not sure if Guadalajara.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
I'll look into it. wrote the name down
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
There you can find the best academic level in the country.It is difficult to get in.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
brief english lesson: It's has several (places?) on the country It has several locations in the country ^^^correct
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
Ohh thank you, that is what i meant with my bad english!
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
There is a Guadalajara's Cinvestav.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
I wish you could just give me little tips like that in spanish, but I've only been taking classes for 2 1/2 months. It'll be awhile befor I'm fluent :( there is?!?!?
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
Don't worry feel free to write in spanish. That is the best way to learn, by practicing
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
Thanks for not laughing at me... or at least thanks for not writing lol!! what 'there is'? where
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
oh mine that was to your last comment about there being a school here I went 'there is?" out of surprise
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
Don't worry =P. I was telling you that there is a Cinvestav located on Guadalajara.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
You can take a look here: http://www.cinvestav.mx/posgrado.aspx
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
Does you gf speaks english?
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
I even have some of the (admission or entrance?) exams. Let me see..
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
Yeah, which has really slowed me down. She has no patience. Everytime I ask her something she says 'that's stupid, why would you ask that?' I will be looking into that school here, I kinda like Guadalajara, and after living in LA for 12 years I don't really want to move to DF more expensive to, right?
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
cool! entrance exam is the term, what is it in spanish?
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
Examen de admisión. That is the reason I get confused.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
right, I tried to say pagar atencion once, I got laughed at, but that's what it is in english "pay attention" not "put attention"
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
again sorry for not having accent marks...
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
Don't worry 70% of mexicans don't know how to use the accent marks.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
But is good that you learn how to use them.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
My roomate spoke spanish at home all his life and was born in DF, but I correct him on things sometimes because I'm learning spanish formally. He never did that.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
You mean your roomate at LA?
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
I think we have the same time zone, right? I know it's not that late, but I think I should try to sleep. I have to do 2 weeks worth of homework tomorrow =(
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
Yeah, it's better to go to sleep. I'm still looking for the entrance exam.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
Thanks for the info on Cinvestav, I'll look into it. And looking for the exam. If you find it I'd be curious to hear what it has.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
Ok, Have a good night, I'm goint to be here tomorrow in case you need some help.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
I may have to take you up on that, thanks! goodnight NoData.
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
what does it means to take something up?
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
"to take someone up on an offer" I said I'd have to take you up on your offer, meaning I may ask you for help with spanish.
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
or just, 'I might take you up on that' for short
 2 years ago

NodataBest ResponseYou've already chosen the best response.2
Well is difficult to learn that in a book or with google traslator. thank you so much. And have a good night again
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.1
yeah expressions are tricky... goodnight :D
 2 years ago
See more questions >>>
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.