Question $3$: Please do in Excel!!!!

A catering company must have the following number of clean napkins available at the beginning of each of the next

four days: day $1$:$15,$ day $2$:$12,$ day $3$:$18,$ and day $4$:$6.$ After being used, a napkin can be cleaned by one of two

methods: fast service or slow service. Fast service costs $$0\mathrm{.}10$ per napkin, and a napkin cleaned via fast service is

available for use the day after it is last used. Slow service costs $$0\mathrm{.}06$ per napkin, and a napkin cleaned via slow

service is available two days after they were last used. New napkins can be purchased for a cost of $$0\mathrm{.}20$ per

napkin.

Part A: Formulate the problem as a minimum cost transportation problem.

Part B: Solve the problem $($provide exact values for all variables and the optimal objective function$).$