Please help me with S1 probability!

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*girlie*
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#1
Report Thread starter 15 years ago
#1
I don't get these at all...! They're from the S1 book:

Pg. 93, ex. 5E

8) I have three 2-pence pieces and two 10-pence pieces in my pocket. I pick two coins out of my pocket at random. Find the probability that they are:
a) both 10-pence pieces
b) both of the same value
c) find the probability that the coins are both the same, given that the first coin was a 2-pence piece.
d) Find the probability that the first coin was a 2-pence piece given that the coins were both the same.
The event T is that the sum of the coins’ values is 20 pence and the event S is that the coins are the same.
e) Find P(T/(not slanted, it’s a straight line!)S).
f) State, with a reason, whether or not events S and T are independent.
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Vishpatel
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Report 15 years ago
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a) 2/5*1/4
b)(2/5*1/4) + (3/5*2/4)
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*girlie*
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eugh i really cant do probability!

9) A box X contains two white balls, one blue ball and three red balls; a box Y contains four white balls, two blue balls and no red balls. An ordinary die is thrown once and, if the score is a 1 or a 6, then a ball is drawn at random from box X, otherwise a ball is drawn from box Y.
a) Draw a tree diagram to represent this experiment.
b) Find the probability that a white ball is drawn.
c) Given that a white ball is drawn, find the probability that the box Y is used.
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*girlie*
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#4
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could somebody PLEASE help me with the second question (9) ?
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J.F.N
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#5
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I'm busy, but I feel bad that no one has helped you. See attachment for 9.
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