(a)[3]
Determine the probability that, over a week of 7 days, snow falls on at least five of them.
(b)[2]
A week that has snow on at least five of the seven days is described as a ‘white’ week. Determine the probability that, among three weeks selected at random, at least one is a white week.
(c)[5]
In another Arctic region, the probability that a week is white is $0.8$. Use a suitable approximation to determine the probability that, in 60 randomly selected weeks, fewer than 47 are white weeks.