字典翻译 问答 高中 数学 【一道英文数学题=Therearefivenumbers.Theiraverageisnine.Ifwechangeonenumbertoone,andanothernumbertotwo,theaveragebecomeseight.Ifwerechangethesetwonumbers:onenumbertotwotimesasmanyasitsoriginalvalue,andtheothe】
问题标题:
【一道英文数学题=Therearefivenumbers.Theiraverageisnine.Ifwechangeonenumbertoone,andanothernumbertotwo,theaveragebecomeseight.Ifwerechangethesetwonumbers:onenumbertotwotimesasmanyasitsoriginalvalue,andtheothe】
问题描述:

一道英文数学题=

Therearefivenumbers.Theiraverageisnine.Ifwechangeonenumbertoone,andanothernumbertotwo,theaveragebecomeseight.Ifwerechangethesetwonumbers:onenumbertotwotimesasmanyasitsoriginalvalue,andtheothertofourtimesasitsoriginalvalue,theaverageofthefivenumberswillbecomethirteen.Whichtwonumbershavebeenchanged?

孔波回答:
  设Therearefivenumbers为ABCDE   则A+B+C+D+E=5*9=45   1+2+C+D+E=5*8=40   2A+4B+C+D+E=13*5=65   解得A=2   B=6   即6and2twonumbershavebeenchanged
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