Expert: Vijilant - 6/26/2006

Question
kindly give us an example of worded problem applying set theory with its set formulas and solution...
thank you.

Answer
Hello Keeren
I cannot be sure what sort of question you want answered, but I will give an example which uses the formula
N(AUBUC) = N(A) +N(B) +N(C) -N(AiB) -N(BiC)-N(Ci) +N(AiBiC)
where I have used i for intersection instead of the usual notation which I can't type.
A supermarket stocks plain, self-raising and brown flour.  Out of 147 shoppers, 100 do not buy any flour at all, 23 shoppers buy plain flour, 17 buy self-raising,and 18 buy brown flour.
6 shoppers buy both plain and self-raising; 3 buy both brown and self-raising; and 4 buy both plain and brown flour.
Calculate the number who buy all three kinds.
With the obvious notation:
N(PUSUB) =N(P) +N(S) +N(B)-N(PiS)-N(SiB) -N(BiP) +N(PiSiB)
Substituting
47 = 23 + 17 + 18 - 6 -3 -4 +N(PiSiB)
from which N(PiSiB) = 2.
If this is not the type of problem you are interested in, please get back to me with more specific information
vijilant