题目

Mistrust Mars Zhengzhou Ride-share Effort More than 300 private car owners from a central Chinese city volunteered to offer free rides to citizens to ease crowded public transportation, but many local people didn't accept the offer for fear of being cheated. The ride-share program was begun in October in Zhengzhou, capital of Henan Province, when Ye Zhantong, a private car driver, started to gather volunteers to offer the free service. The drivers tied a green silk ribbon (丝带) on the car to differentiate themselves from unlicensed taxi drivers. But the free rides haven't been popular一批灯泡120只，其中20 W、40 W、60 W的数目之比为4∶3∶1，现用分层抽样的方法产生一个容量为40的样本，三种灯泡依次抽取的个数为_________________.