1) in a particular area, 30% of men and 20% of women are underweight. four men and three women work in an office.
find the probability that there are 2 underweight people in the office.
2) on her drive to work stella has to go through four sets of traffic lights. she estimates that, for each set, the probability of her finding them red is 2/3 and green 1/3. (she ignores the possibility of them being amber) stella also estimates that when a set of lights is red she is delayed by one minute.
find the expected extra journey time due to waiting at lights.
for this question i did 4X(2/3)= 8/3
for that its 2.666 recurring however the answer is 2mins and 40 secs. where did the 40 sec come from?