$*************$excel formula for this questions$************************$How to find part C of this question??? RentAPhone is a new service company that provides European mobile phones to American visitors to Europe. The company currently has $80$ phones available at Charles de Gaulle Airport in Paris. There are, on average, $25$ customers per day requesting a phone. These requests arrive uniformly throughout the $24$ hours the store is open. The corresponding coefficient of variation is $1.$ Customers keep their phones on average $72$ hours. The standard deviation of this time is $100$ hours.

a$.$ What is the average number of telephones the company has in its store?

b$.$ How many customers, on average, are waiting for the phone?

c$.$ What is the average waiting time per customer if the company decides to limit all rentals to exactly $72$ hours? Assume that if such a restriction is imposed, the number of customers requesting a phone would be reduced to $20$ customers per day $($everything else is kept the same as before$).$Inputs for part a and b Inputs for part c

a$=0\mathrm{.}96$ hr a$=0\mathrm{.}96$ hr

p$=72$ hr p$=72$ hr

CVa$=1$ CVa$=1$

CVp$=1\mathrm{.}39$ Average time a customer keeps the phone CVp$=1\mathrm{.}39$

m$=80$ m$=80$

Utilization$=94\%$ Utilization$=93\mathrm{.}75\%$

Tq$=$ hours Tq$=$ hours

Service factor $0\mathrm{.}900$ formula given Service factor $0\mathrm{.}900$ formula given

Utilization factor $7\mathrm{.}506$ formula given Utilization factor $7\mathrm{.}506$ formula given

Varability factor $1\mathrm{.}465$ formula given Varability factor $1\mathrm{.}465$ formula given

# of Phones unused $7575$

#Phone are avaliable $55*******$EXCEL FORMULA $********$