Do not actually solve the questions. First I need to know what problem it is for example (Binomial probability distribution, NB, PMF, CDF, COMBINATORICS, conditional problem, independence, RV`s, and poisson distribution..etc ) Second please just tell relevant formulas and ideas that would use to solve the questions. ASAP will thumbs up thank you.

3) a. If the number of months that the COVID-19 epidemic is supposed to endure for follows the following distribution X 2 3 6 9 12 () .1 .3 .35 .15 .1 What is the expected amount number of months we expect the epidemic to last? b. Say that the number of cough masks available is a linear function of how long Covid lasts. Say that there are 1 million masks already and another 5 million masks are made per month that Covid lasts. If the epidemic is expected to last 2 months, what is the expected number of masks?