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Two probability problems (1 Viewer)

Nevermore

Godlike
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35
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HSC
2009
Please explain how you do it so that i may understand, thank you:eek:


1. <table bgcolor="#d3d3d3" border="0" cellpadding="0" cellspacing="0" width="65%"><tbody><tr><td valign="top" width="20"></td> <td>In a school, 14% of students take drama and computer classes, and 67% take drama class. What is the probability that a student takes computer class given that the student takes drama class? </td></tr></tbody></table>



2. <table bgcolor="#d3d3d3" border="0" cellpadding="0" cellspacing="0" width="65%"><tbody><tr><td valign="top" width="20">
</td> <td>In a class of 30 students, there are 17 girls and 13 boys. Five are A students, and three of these students are girls. If a student is chosen at random, what is the probability of choosing a girl or an A
student?
</td></tr></tbody></table>
 

x3.eddayyeeee

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Use the product rule of probability.
1. P(both subjects) = 14/100 x 67/100

Use general rule. non mutually exclusive events.
2. P(A or B) = P(A) + P(B) - P(AB)
= 17/30 + 5/30 - 3/30

*should be right* O__O"
 
Last edited:

Nevermore

Godlike
Joined
Nov 4, 2008
Messages
35
Gender
Male
HSC
2009
Thanks mate,
i get the second one now, but the first one isn't just as easy as fast. :cool:
 

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