题干

某校开展了以“人生观、价值观”为主题的班会活动,活动结束后,初三(1)班数学兴趣小组提出了5个主要观点并在本班50名学生中进行了调查(要求每位同学只选自己最认可的一项观点),并制成了如下扇形统计图.

(1)该班学生选择“和谐”观点的有几个人,在扇形统计图中,“和谐”观点所在扇形区域的圆心角是多少度

(2)如果该校有400名初三学生,利用样本估计选择“感恩”观点的初三学生约有多少人.

(3)如果数学兴趣小组在这5个主要观点中任选两项观点在全校学生中进行调查,求恰好选到“和谐”和“感恩”观点的概率.(用树状图或列表法分析解答)

 

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解:(1)该班学生选择“和谐”观点的有:50×10%=5(人);“和谐”观点所在扇形区域的圆心角是:360°×10%=36°;故答案为:5,36;(2)选择“感恩”观点的初三学生约有:400×28%=112(人);故答案为:112;(3)列表法得:
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    Many cities and towns have laws that require people to recycle paper and plastics. Now some state and local governments have passed laws that require citizens to recycle their food waste as well. California and Vermont have statewide laws about recycling food waste that apply to businesses and homes. The process of recycling food waste and turning it into usable soil is called composting(堆制肥料).

    Food waste that can be composted includes fruit and vegetable peels, coffee grounds, tea bags, and eggshells. Garden waste such as stems and leaves can also be composted. Meat, fish, and dairy food waste cannot be recycled.

According to environmental groups, composting reduces the amount of trash going into landfills(垃圾填埋池), and composted waste holds a wide range of nutrients. When compost is added to the soil in gardens and fields, it helps crops grow.

    Reducing the amount of waste that goes into landfills is one reason why cities and states are passing food-waste recycling laws. “Our landfills are far from enough for the creation of new ones is shrinking.” Renee Crowley, a project manager said.

    Officials in Seattle, Washington, say that food waste makes up 30% of the trash going into landfills, and they are looking to reduce that percentage. That city has a law requiring people to recycle food waste. It is banned from all garbage. There is a fine for people who put it into regular garbage.

    Crowley points out that even in cities where food recycling is not a law, there are often places where citizens can drop off their food waste for composting. Many schools and colleges have also started composting programs.

    Those who are against food-recycling laws say that the composting process is costly. In addition, it can be difficult for people who live in apartments to store their waste because they don't have access to outside storage bins. Patti Ferguson from Orange County, California, told her local newspaper that she thought an indoor container containing food waste would get smelly.