Two professors: Prof. Strange and Prof. Boring.
100 published papers. 45% published by Strange. 35% published by Boring. 10% of the papers involve both professors.
Let A denote publication by Strange
Let B denote publication by Boring
P(A intersect B) = .1
How many of the published papers were authored by:
a.) neither Strange nor Boring?
addition rule: P(A union B)= P(A)+P(B)-P(A intersect B), resulting in
P(A union B) = .7, or 70 papers involved either professor, take the compliment of P(A union B),meaning:
30 papers have nothing to do with Strange nor Boring.
Now, where I get confused:
b.) How many published papers were authored by at most one of these two professors?
How would I go about answering this?