I was reading one of walker's posts today and something

I was reading one of walker's posts today and something about it clicked with how I see Venn Diagrams and Set Theory. It's nothing too crazy, it's just that I'm not one to jump right to a formula...I like the visual part of the Venn diagrams and so I use them, but they're not always the easiest (or quickest) way to solve a problem.

If you have 3 overlapping groups, lets says athletes in school. Soccer players, basketball players, and golfers.

total of 100 athletes, some play all three, some play only 2, but everyone plays at least 1 sport.

S= Soccer
B=Basketball
G=Golfer
SBG = All three
SB = Soccer + Basketball
SG = Soccer + Golf
BG = Basketball + Golf

Lets say you have 60 basketabll players, 33 soccer players, and 14 golfers. The formula to set this up would be:

100 = (S + B + G) - SB - SG - BG - SBG

Lets substitute in what we know:

100 = 33 + 60 + 14 - SB - SG - BG - SGB

Of course, we don't yet have enough information to answer the question, but this seems like a much better way to organize the problem rather than in picture/diagram form.

Lets say we also know "Everyone that plays Golf also plays basketball."

100 = 30 + 60 + 14 - SB - SG - 14 - SGB

Can anyone provide links to some problems to use this stuff on? I think it's a very quick way to solve these types fo problems, but it would certainly help to have some practice problems.

hope this helps someone.