Question

Dawson's "Last Stop BBQ" restaurant recently opened a drive-thru. Steven, the manager, is concerned that their processes are not efficient enough to satisfy the lunch-hour rush. Based on the information in the table, please answer the following questions. Assume operations are for only 1 hour unless otherwise stated.If steven needs to process 320 orders per 4-hour shift, how many employees will he need

Step	Time (seconds)	Immediate Predecessors
A. Take order	25
B. Collect money at window	20	A
C. Gather drinks	40	A
D. Gather food	32	A
E. Put drinks and food in bag	16	C, D
F. Give the order to the customer	20	B, E

Answer 1

Case details

• Dawson's "Last Stop BBQ" restaurant recently opened a drive-thru.
• Steven, the manager, is concerned that their processes are not efficient enough to satisfy the lunch-hour rush.
• Based on the information in the table, please answer the following questions.
• Assume operations are for only 1 hour unless otherwise stated.
• f Steven needs to process 320 orders per 4-hour shift, how many employees will he need?

Analysis

• As given in the question 320 orders per 4-hour shift
• This implies 80 orders on a 1-hour basis.

Step	Task	Time (in secs)	Immediate predecessors
A	Take order	25
B	Collect money at window	20	A
C	Gather drinks	40	A
D	Gather food	32	A
E	Put drinks and food in bag	16	C,D
F	Give the order to the customer	20	B,E

We need to find out the critical path and the minimum time taken to full fill one order.

Total time taken to furnish 1 order = 25 secs (from A) + 20 Secs (from B) + 20 secs (extra 20 secs for C from a total of 40 secs as 20 are run in parallel to B) + 0 secs for D (as all 32 secs are covered under the tasks done by B and C) + 16 secs for E and 20 secs for F = 101 secs

Now, it is given in 1 hour = 80 orders and for 1 order time taken is 101 secs end to end steps.

1 order takes	101 sec	1.6833	mins
Now, in 60mins orders handled could be	60/1.6833	35.644	Order
As per the question	80 orders	in 60 mins is expected
In order to handle 80 orders staff needed	80/35.644	2.2 staffs for 1 hr basis

So, a minimum of 2.2*4 = 8.8 ~ 9 staff for a 4-hour shift handling 320 orders is recommended.

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