In a village with a population of 1500,the probability of a person falling sick is 0.002. Find the probability that
a)3people fall sick in a week
b)less than 3 fall sick in a week
c)at most 3 fall sick in a week
d)more than 2 fall sick in a week
this is a binomial probability
... sick (.002) or not sick (.998)
... (n + s)^1500
expanding ... n^1500 + 1500 n^1499 s +
1500C2 n^1498 s^2 + 1500C3 n^1497 s^3 + ...
a) 4th term
b) sum of 1st three terms
c) sum of 1st four terms
d) 1 - [answer b)]