问题 解答题

某运输公司有12名驾驶员和19名工人,有8辆载重量为10吨的甲型卡车和7辆载重量为6吨的乙型卡车.某天需运往A地至少72吨的货物,派用的每辆车需满载且只运送一次,派用的每辆甲型卡车需配2名工人,运送一次可得利润450元;派用的每辆乙型卡车需配1名工人,运送一次可得利润350元.该公司该如何合理计划当天派用两类卡车的车辆数,可得最大利润,最大利润是多少元?

答案

设派用甲型卡车x辆,乙型卡车y辆,获得的利润为z元,z=450x+350y…(2分)

由题意,x、y满足关系式

0≤x≤8
0≤y≤7
0<x+y≤12
10x+6y≥72
0<2x﹢y≤19
x∈Z,y∈Z

作出相应的平面区域如图阴影部分所示…(8分)

z=450x+350y=50(9x+7y)

x+y=12
2x+y=19
得交点(7,5)…(10分)

∴当x=7,y=5时,450x+350y有最大值4900

答:该公司派用甲型卡车7辆,乙型卡车5辆,获得的利润最大,最大为4900元…(12分)

阅读理解

阅读理解 。

     Mary Quant was born in 1934. When she was young, there was no teenage fashion. Young women

were dressed like grown ups or little girls. At thirteen, she designed her own school uniform. She wore

short dresses and long socks. After school, Mary went to Goldsmith's College in London.  She didn't enter the college gate but she met her future husband, Alexander Green. Like Mary he wore unusual clothes,

such as purple velvet trousers and pajamas jackets.     In 1955 Mary left college and worked for a hat

maker in London's West End.  But soon they opened their own shop.  It was called Bazaar and it was

the first small shop for women in the King's Road in Chelsea.  Mary designed all the clothes and made

them on her old sewing machine.      The 1960s are often called the "Swinging Sixties".  During these

years Mary's designs became very popular.' Everyone loved her mini-skirts and colored tights. Thanks

to Mary, London became the fashion capital of the world.     Mary's fashion showed different a lot from

what they had been before.  Mary's models didn't walk they danced to pop music.      Soon Mary's fashion clothes became popular in America, too.      At the age of 37, Mary had a son, Orlando.  She says,  

"Becoming a mother was quite the most important thing that ever happened to me. "     In 1966, Mary was awarded the O. B. E.   (a special medal given by the Queen). She went to Buckingham Palace in a mini

skirt to collect the medal.    

根据短文内容 ,回答下列问题 。

1.What did she do when she was thirteen years old?

                                                                         

2.  How old was she when she left college?

                                                                         

3.  What did she do first when she left college?

                                                                        

4.  What's the name of her own shop?

                                                                       

5. What did London become thanks to Mary?     

                                                                        

单项选择题 A3/A4型题