标题: GWD题，急求，在线等！ [打印本页] 作者: sierrapan 时间: 2009-11-21 10:28 标题: GWD题，急求，在线等！ Before a certain tire is used, 40 percent of its total weight consists of tread. If during a lifetime of use, 50 percent, by weight, of the tire's tread is lost and no other parts of the tire is lost, what per cent of the tire's total remaining weight consists of the remaining tread?作者: sierrapan 时间: 2009-11-21 10:29
答案25%作者: wuwei_carol 时间: 2009-11-21 10:54
40%*(1-50%)/(1-40%*50%)作者: sierrapan 时间: 2009-11-21 10:57 谢谢！
谢谢！