need help as soon as possible!

[izzypop08]

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!!!

 

[tkhunny]

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 .

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.

 

[Deleted member 4993]

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!!!

 

[Aladdin]

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 .

-------------------------------------------------------------------------------------------------------------------------------------------------------
a)With replacement : P(2 red marbles)= 2C7 / 2C10

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