How do we know in probability question that its AND or OR
question. AND = Multiplication Please help, i'm messing up
simple problems because of this little confusion. if you're
calculating the probability of MULTIPLE events occurring, you
always MULTIPLY; if you're calculating the probability of
ALTERNATIVE events occurring, you ADD. Some common multiple
event words: "and", "both" and "all". Some common alternative
event words/phrases: "or", "at least" and "at most". On the
toughest probability questions, you may have to do a bit of
both. For example: At a certain university, the probability of
getting on campus housing in any given year is 1/3. If Yohann
enters the lottery two years in a row, and if each lottery is
independent, what's the probability that Yohann gets housing in
exactly one of the two years? Since there are two years, there
are four possible scenarios for Yohann: 1) Yr 1 housing, Yr 2
housing; 2) Yr 1 housing, Yr 2 no housing; 3) Yr 1 no housing,
Yr 2 housing; and 4) Yr 1 no housing, Yr 2 no