b$.$ How much time, on average, does a student spend waiting in line?

Note: Do not round intermediate calculations. Round your answer to $1$ decimal place.

Average time minutes

c$.$ How long is the $($waiting$)$ line on average?

Note: Round your answer to $2$ decimal places.

Average length of the waiting line customers

d$.$ What is the probability that an arriving student $($just before entering the Administrative Services Office$)$ will find at least one other student waiting in line?

Note: Do not round intermediate calculations. Round your answer to $2$ decimal places.

Probability

$\%$