p.p1%252520%25257Bmargin%25253A%2525200.0px%2525200.0px%2525200.0px%2525200.0px%25253B%252520font%25253A%25252012.0px%252520%252526%25252339%25253B.PingFang%252520SC%252526%25252339%25253B%25257D%25250Aspan.s1%252520%25257Bfont%25253A%25252012.0px%252520%252526%25252339%25253BHelvetica%252520Neue%252526%25252339%25253B%25257D某制造公司每年以单价8元购入10000单位某物料。每次订货成本为25元，单位年保管成本为2元，求经济订货周期？