b$.$ What is the probability that the project can be completed in $24$ days or less? In $21$

days or less? $($Round your $t_e$ and $z$ values to $2$ decimal places and "Standard

deviation" to $3$ decimal places. Round your final answers to $4$ decimal places.$)$

c$.$ Suppose it is now the end of the seventh day and that activities A and $B$ have been

completed while activity $D$ is $50$ percent completed. Time estimates for the

completion of activity $D$ are $5,6,$ and $7.$ Activities $C$ and $H$ are ready to begin.

Determine the probability of finishing the project by day $24$ and the probability of

finishing by day $21.($Round your intermediate calculations to $3$ decimal places and

final answers to $4$ decimal places.$)$