Ghostbusters counting problem - page 153 in section 3.3. Venn diagrams and the principle of inclusion/exclusion
HOMEWORK #6 HINTS/HELP/Animated GIFs ...
Speaking of 1, 5, 10, 10, 5, 1:
In any set with 5 elements, there will be 2 to the 5th power subsets or 32 elements in the PowerSet, which is the set of all possible subsets: