Question

1. CC Car Wash specializes in car cleaning services. The services offered by the company, the exact service time, and the resources needed for each of them are described in the table following:

   Service	Description	Processing Time	Resource
   A. Wash	Exterior car washing and drying	10 minutes	1 automated washing machine
   B. Wax	Exterior car waxing	15 minutes	1 automated waxing machine
   C. Wheel Cleaning	Detailed cleaning of all wheels	16 minutes	1 employee
   D. Interior Cleaning	Detailed cleaning inside the car	20 minutes	1 employee

   The company offers the following packages to their customers:

   • Package 1: Includes only car wash (service A).

   • Package 2: Includes car wash and waxing (services A and B).

   • Package 3: Car wash, waxing, and wheel cleaning (services A, B, and C).

   • Package 4: All four services (A, B, C, and D).

   Customers of CC Car Wash visit the station at a constant rate (you can ignore any effects of variability) of 50 customers per day. Of these customers, 30 percent buy Package 1, 30 percent buy Package 2, 15 percent buy Package 3, and 25 percent buy Package 4. The mix does not change over the course of the day. The store operates 10 hours a day.

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   For the next summer, CC Car Wash anticipates an increase in the demand to 80 customers per day. Together with this demand increase, there is expected to be a change in the mix of packages demanded: 40 percent of the customers ask for Package 1, 30 percent for Package 2, 20 percent for Package 3, and 10 percent for Package 4. The company will install an additional washing machine to do service A. Answer the following questions based on this new situation.

   e. What is the implied utilization rate for the washing machines? Round your answer to the nearest whole number and ignore the percentage sign. For example, if your answer is 0.45 or 45%, fill in 45; if your answer is 0.76 or 76%, fill in 76.

   Your answer is .

Answer 1

Answer:

All the packages include car wash. Hence, all the packages utilise washing machine.

Time taken by washing machine for single customer = 10 minutes

Total time for which the washing machine is utilised on normal days = 50 x 10 minutes = 500 minutes

During next summer, the number of customers visit = 80

Since there are two washing machines, let us assume that the numbers of customers being distributed and processed on the machine are in alternate numbers i.e. one customer if allotted to machine 1, then next customer will be allotted to machine 2 and so on.

Thus, washing machine 1 will take 40 customers and washing machine 2 will take another 40 customers.

Time taken by washing machine for single customer = 10 minutes

Total time for which washing machine 1 is utilised = 40 x 10 = 400 minutes

Total time for which washing machine 2 is utilised = 40 x 10 = 400 minutes