Stuck on Venn Diagram

I am stuck on a Venn diagram question...there are three circles Circle A has a 6 alone, circle B has a 9 alone circle c has a 10 alone. Where A and B meet there is a 5. Where A and C meet there is a 7. Where B and C meet there is a 6. Where A,B, and C meet there is a 1. There is an 8 outside the circles.

The question is: P (A or B)

I am using (19/49 + 21/49) - 6/49=.694

I am not getting this correct and can't figure out why! Any help would be appreciated.

Judging solely by what you have posted, I interpret the problem as being something like the following:


The above Venn diagram would then represent a dart board, and the numbers in each circle represent the probabilities of a dart landing in that region. If that's the case, then I'd begin by noting that the sum of all the numbers present in the diagram is 52, so that could be a large part of why you're getting the wrong answer. If, however, my interpretation is not correct, please post the full text of the exercise, including any and all instructions you've been given about how to solve these types of problems. If possible, please quote directly from your book or post a picture. Thank you.

My 49 was supposed to be a 44, my mistake. If calculating the probability of A or B, are you supposed to add the 8 that is outside the circles?

tex_913 said:

I am stuck on a Venn diagram question...there are three circles Circle A has a 6 alone, circle B has a 9 alone circle c has a 10 alone. Where A and B meet there is a 5. Where A and C meet there is a 7. Where B and C meet there is a 6. Where A,B, and C meet there is a 1. There is an 8 outside the circles.

The question is: P (A or B)

I am using (19/49 + 21/49) - 6/49=.694

I am not getting this correct and can't figure out why! Any help would be appreciated.

Click to expand...

Why are you adding the numbers together? They are just elements. For example, 10 is one element out of 4 elements in circle c so that the probability of getting a 10 given circle c is 1/4.