Date: 4 Jun 1995 12:15:53 -0400 From: Anonymous Subject: Probability 6th grade math problem: There's a box with 12 letters, one of which is a D, and 2 are E's. I know that the probability of getting a D is therefore 1 out of 12, and an E is 1 out of 6. However, how do I determine the probability of getting a D and then an E, if the D is replaced after being selected?
Date: 6 Jun 1995 12:28:53 -0400 From: Dr. Ken Subject: Re: probability Hello there! You can find out how many different favorable possibilities there are for drawing, and then divide that by the total number of possibilities for drawing. In this case, there are 2 different ways you can get a D and then an E. You can draw the D and then the first E, or you can draw the D and then the other E. Now how many different ways are there you can draw 2 letters from the bag? Well, since there are 12 possibilities for each draw, there are 12x12 = 144 possibilities. So the probability we get a D and then an E is 2/144, or 1 out of 72. Thanks for the question! -Ken
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