列主消元法练习 一个城镇有三个主要企业：煤矿、电厂和铁路作为它的经济系统。

 　　生产价值1元的煤(产品1)，需消耗0.3元的电费(中间产品2)和0.2元的运输费(中间产品3)；

 　　生产价值1元的电(产品2)，需消耗0.4元的煤费(中间产品1)、 0.1元的电费和0.1元的运输费；

 　　提供价值1元的铁路运输服务(产品3)，需消耗0.3元的煤费和0.2元的电费和0.2元运输费。

在某个星期内，除了三个企业间的彼此需求，煤矿得到6万元的订单(即最终产品1)，电厂得到3万元的电量供应要求(即最终产品2)，而地方铁路得到价值5万元的运输需求(即最终产品3)。

-Column elimination law practice in a town has three main businesses: coal mines, power plants and railways as its economic system. 　production of $ 1 worth of coal (1), 0.3 yuan in electricity consumption (intermediate product) and 0.2 yuan of transportation costs (intermediate products)　　the production value of $ 1 electricity (2), need to consume coal fee of 0.4 yuan (intermediate products), the tariff of 0.1 yuan and 0.1 yuan of transportation costs　　$ 1 worth of rail transport services (products), the cost of the coal charge of 0.3 yuan and 0.2 yuan in electricity transportation fees and 0.2 yuan. In a week, in addition to the three enterprises each other needs, coal 6 million orders (ie, the final product 1), power plant to get $ 30,000 in electricity supply requirements (ie, the final product 2), while the local railway 5 million worth of transportation needs (ie, the final product 3).