Mr. Grease's class is conducting an experiment to find the probability of pulling certain colors from a bag of 25 marbles. If 4 are purple, 7 are yellow, 2 are green, and the rest are black, what is the probability of drawing a purple marble and then a yellow marble if the marbles are replaced after they are drawn?

Question

mathmale · Answer

I see that the "sample space" consists of a total of 25 marbles, of which 4 are purple, 7 are yellow, and so on.  What is the prob. of drawing a purple marble?
Now if we put that purple marble back into the bag and mix up the marbles a bit, what is the prob. of drawing a yellow marble?  Note that the draws are entirely independent of one another.

So, to answer this question, take the 2 probabilities you've just calc. and mult. them together; the result will be the prob. that you first draw a purple marb. and then a yellow one.