# 311T Study Guide

## 311T Study Guide

• Submitted By: lujiaoli
• Date Submitted: 02/07/2016 12:38 AM
• Words: 1291
• Page: 6

﻿Utilization = (flow rate) / (capacity available)
= (500 bags per day) / (8*66.67 bags per day)
= 93.75%

RATE=TR, Average

The throughput rate is 30 buses per hour.
The throughput time is 20/60 =1/3 hours

TR = 15 plans per hour.
TT = (0.75 +4.25)/60 = 1/12 of an hour
WIP = TT*TR = 15*1/12 = 1.25

Suppose TR = 20,000 and TT = 1. Then WIP = TR*TT = 20,000 units.
But in this case
TR = 10,000 + 0.1WIP = 10,000+0.1*20,000 = 12,000 < 20,000.
Thus the firing was not justified.

To achieve the objective of TR = 20,000, the company must have WIP = 100,000. In this case the TT = 100,000/20,000 = 5month.

(d) (5 points) If Casey only opens her business for 5 hours every day, how many orders can she fulfill daily? (You may allow for a fractional order.)
5 hours = 300 minutes
Cycle time of the entire process is determined by the bottleneck – packaging. So it is 2.5 min.
Total number of orders = (300-6.5)/2.5 + 1 = 118.4 ≈ 118
Number of orders in 5 hours= 1+ (300- 6.5)/2.5 -= 1+ 117.4=118.4

The manager, Mr. Money, decided not to buy a machine. He still has 10 washers and 15 dryers. The manager estimates that on average Money Laundry receives 8 orders every hour. The manager also finds that on average there are 5 orders in the washing stage and 7 orders in the drying stage.

a. What is the utilization of washers, on average?
8 orders/hour / 20 orders/hour = 40%

b. What is the utilization of dryers, on average?
8 orders/hour / 22.5 orders/hour = 35.56%

c. On average, how long does it take an order to finish washing process, from the time the order is received?
WIP = 5, TR = 8 orders/hour
TT = WIP / TR = 5/8 = 0.625 hour or 37.5 minutes

d. On average, how long does it take an order to finish drying process, from the time the order finishes the washing process?
WIP = 7, TR = 8 order/hour
TT = WIP / TR = 7/8 = 0.875 hour or 52.5 minutes

e. On average, how long does an...