00:01
A, we are assuming that we have a bag, and this bag contains four green marbles, six white, and 10 red.
00:11
So in total, this recording the color, what we have is 20 marbles, right, in the back.
00:22
So in this item, we were saying that we are, in this case, selecting two marbles, but when they say that they are being replaced, this means that this is with replacement.
00:35
This basically means that i pick, i choose like one marble from the bag.
00:41
I pick one, but then i put the same marble back into the bag.
00:46
So this means that this number of marbles in the back will never change, will always be 20.
00:52
If they don't say anything about if they are putting back or not, this means that we should assume that it's without replacement.
00:59
That once they draw one ball, they will not put that ball back into the back.
01:07
So this means that this value would change.
01:09
But for the item a, we are assuming that this value does not change because of the word replaced.
01:16
So here, basically, they are saying what is the probability of the first one being green and the second one being red.
01:27
So we just need to think about each one independently.
01:31
So out of the 20 box, how many of them are green? so i have four options.
01:37
So this means that this is the probability of picking one green in the bag.
01:42
Then, now that i already select one, i need to consider how many marbles i have in the bag now...