题干

《九章算术》之后,人们进一步用等差数列求和公式来解决更多的问题,《张丘建算经》卷上第22题为:今有女善织,日益功疾,且从第2天起,每天比前一天多织相同量的布,若第1天织5尺布,现在一月(按30天计)共织390尺布,则每天比前一天多织        尺布.(不作近似计算)

A:12

B:815

C:1631

D:1629

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答案(点此获取答案解析)

D

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阅读理解

    What is the hottest topic at your school recently? In Taiyuan No.55 Middle School,it's money.

    The school held an activity called “making money” last weekend.About 200 Junior 1 and Junior 2 students were divided into 30 teams.They went out to make money by selling things.

    What did they choose to sell? Some sold newspapers;some chose bottled water;some sold environmentally friendly shopping bags and bamboo bamboo baskets.

    Hu Qing's team decided to sell some useful books in front of the Children Activity Center.They thought parents would like to buy the books for their children.But unfortunately,they met urban management officers(城管).The officers asked them to leave.“ We played hide-and-seek(捉迷藏)with the officers for the whole morning”said Hu. “Finally we had to give up.”

    Wang Bing and her team sold ice cream in a square.They didn't meet any officers.But few people were interested in what they were selling.The team then put up a board saying “For Country Kids”.It worked.More people came to their stall(小摊).A foreigner even gave them 100 yuan. “He didn't want any change.He said he wanted to help the children,” said Wang.“ We were touched.” Later that day they gave the 100 yuan and more to the “Project Hope” office.

    Meng Zhaoxiang and his team were luckier.They sold all their cakes in four hours,spending 39.5 yuan and getting back 80 yuan.They made 40.5 yuan.“It was not easy to make the money,” said Meng.“ Some people just looked.Others just tasted but didn't buy.Now I know how hard it is for our parents to make the money we need to lead happy lives.”