Question 425917
probability of each man surviving another year is .98


probability of all 5 men surviving another year is.98^5 = .903920797


probability at least 1 man does not survive = 1 - .90392079 = .096079203


p(a and b and c and d and e) = p(a) * p(b) * p(c) * p(d) * p(e)


if p(something happening) = x, then p(something not happening) = 1-x.


that something either happens or it doesn't happen, and the sum of all the probabilities is always equal to 1.


if x = all 5 survive, then not x means not all survive.


not all survived means that at least 1 or them has not survived.


p(not x) = 1 - p(x)