# Please need help with probability question before exam tmw

• Feb 10th 2013, 12:56 PM
MathJack
Please need help with probability question before exam tmw
The question is..

A, B and C are events of a sample space headphones(cant find symbol). Obtain expressions for each of the following events:

a. exactly one occurs;

b. exactly two occur;

c. at most two occur

d. both B and C occur but not A
• Feb 10th 2013, 01:06 PM
Plato
Re: Please need help with probability question before exam tmw
Quote:

Originally Posted by MathJack
A, B and C are events of a sample space headphones(cant find symbol). Obtain expressions for each of the following events:
a. exactly one occurs;
b. exactly two occur;
c. at most two occur
d. both B and C occur but not A

I will do one of these. BUT you must respond with attempts on the other three.

a) $\displaystyle (A\cap\overline{B}\cap\overline{C})\cup(\overline{ A}\cap B\cap\overline{C})\cup(\overline{A}\cap\overline{B }\cap C)$

Where $\displaystyle \overline{D}$ is the complement of $\displaystyle D$
• Feb 10th 2013, 02:03 PM
MathJack
Re: Please need help with probability question before exam tmw
Thanks Plato, Please let me know if these are correct. Also it looks like its asking for a probabilistic expression, am I wrong?

b. (AnBnC') U (AnB'nC) U (A'nBnC')
c.Is this a union of part a. and b. ?
d. (BnCnA')

Thanks please let me know if these are correct
• Feb 10th 2013, 03:19 PM
Plato
Re: Please need help with probability question before exam tmw
Quote:

Originally Posted by MathJack
Thanks Plato, Please let me know if these are correct. Also it looks like its asking for a probabilistic expression, am I wrong?
b. (AnBnC') U (AnB'nC) U (A'nBnC')
c.Is this a union of part a. and b. ?
d. (BnCnA')
Thanks please let me know if these are correct

Parts b & d are correct.

But not part c.
c) is none, one, or two but not three.

$\displaystyle \overline{A\cap B\cap C}=\overline{A}\cup\overline{B}\cup\overline{ C}$