问题 问答题 计算题

某金属公司销售钢材,过去12周,每周的销售的钢格分别是160、175、165、180、185、170、170、165、175、170、164和168吨。如果它服从正态分布,订货进货的提前期为一周,一次订货费用200元,钢材每吨每周的保管费为10元,要求库存满足率为90%。如果用定量订货法,那么订货点与订货批量分别是多少?(库存满足率为0.9,此时的安全系数为1.28)

答案

参考答案:

(1)由题意可知,需求速率是一个随机变量,订货提前期是一个常量,则

周平均需求量;

标准差

该公司的需求量服从以170.6为平均值、6.84为标准差的正态分布。

(2)由于订货提前期L=1周,F(z)=0.9,查安全系数表得z=1.29,则

安全库存量

由(1)可知,平均需求速度Rd=170.6吨/周,则

订购点ROL=平均需求速度×备运时间+安全库存量=(Rd×L)+S=1×170.6+8.82=179.42(吨)。

(3)由题可知每吨钢材每周持有成本K=10元,订购成本C=200元,则

经济订购批量

即该金属公司的订货点为179.42吨,订货批量为82.6吨。

单项选择题
听力题

B.根据短文内容及首字母提示,填写所缺单词,使短文意思完整。每空限一词。

One day, an old couple around the age of 70 walked into a lawyer’s office. They were there to get a divorce(离婚). The lawyer(律师) was very puzzled. A  1  having a chat with them, he got their story.

This couple had been quarrelling in their 40 years of marriage and nothing ever seemed to go right. They stayed together because of their children. Now all their children have grown up and have their o  2  families. There’s nothing else the old couple have to w  3  about. All they want is to live their own life, so both have agreed on a divorce.

The lawyer was having a hard time trying to get papers done. He couldn’t understand why the old couple w  4   a divorce. While they were signing the papers, the wife told the husband, “ I really love you, but I really can’t carry on any more.”

“It’s Ok, I understand,” said the husband. Looking at this, the lawyer suggested a d   5   together, just the three of them. The wife thought, why not, since they were still going to be f  6  .

The first dish was roasted chicken. At once, the old man took the chicken leg and gave it to the old lady. “Take this, it’s your f  7  .

Looking at this, the lawyer thought maybe here was a chance, but the wife looked

u  8   when she answered, “This is the problem. You always think so highly of yourself and never think about how I feel. Don’t you know that I h  9  chicken legs?”

Little did she know that, over the years, the husband had been trying many d  10  ways to please her; little did she know that chicken legs were her husband’s favourite.