need help as soon as possible!

I

izzypop08

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Joined
Jul 21, 2010
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6
Assume a jar has 7 red marbles and 3 black marbles. Draw out 2 marbles with and without replacement. Find the requested probabilities.
(a) P(2 red marbles)
With replacement , without replacement .

(b) P(2 black marbles)
With replacement , without replacement .

(c) P(one red and one black marble)
With replacement -21/50 , without replacement .

(d) P(red on the first draw and black on the second draw) ---->how do u calculate it on the second draw???? im so lost
With replacement , without replacement .

do i put them out of ten or eight since you are drawing two marbles? i have absolutely no idea how to go about these problems! any explanation for them would help greatly!!!
 
izzypop08 said:
Assume a jar has 7 red marbles and 3 black marbles. Draw out 2 marbles with and without replacement. Find the requested probabilities.
(a) P(2 red marbles)
With replacement , without replacement .
Click to expand...
I'd love to see your efforts. What's the probability of a red on the first draw. You MUST be able to answer this or we cannot proceed.
 
izzypop08 said:
Assume a jar has 7 red marbles and 3 black marbles. Draw out 2 marbles with and without replacement. Find the requested probabilities.
(a) P(2 red marbles)
With replacement , without replacement .

(b) P(2 black marbles)
With replacement , without replacement .

(c) P(one red and one black marble)
With replacement -21/50 - how did you get that? please show work, without replacement .

(d) P(red on the first draw and black on the second draw) ---->how do u calculate it on the second draw???? im so lost
With replacement , without replacement .

do i put them out of ten or eight since you are drawing two marbles? i have absolutely no idea how to go about these problems! any explanation for them would help greatly!!!
Click to expand...
 
izzypop08 said:
Assume a jar has 7 red marbles and 3 black marbles. Draw out 2 marbles with and without replacement. Find the requested probabilities.
(a) P(2 red marbles)
With replacement , without replacement .
Click to expand...
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a)With replacement : P(2 red marbles)= 2C7 / 2C10

Without replacement : P(2 red marbles) = (7/10)(6/9)
 
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