$3\mathrm{.}23$ Using PERT, Adam Munson was able to determine

that the expected project completion time for the construction of

a pleasure yacht is $21$ months, and the project variance is $4.$

a$)$ What is the probability that the project will be completed in

$17$ months?

b$)$ What is the probability that the project will be completed in

$20$ months?

c$)$ What is the probability that the project will be completed in

$23$ months?

d$)$ What is the probability that the project will be completed in

$25$ months?

e$)$ What is the due date that yields a $95\%$ chance of completion?

$3\mathrm{.}29$ What is the minimum cost of crashing the following

project that Roger Solano manages at Slippery Rock University

by $4$ days?