数学题，急求解答！先谢谢大家了，要说明方法，如果是英文的更好

Question

1.Ataparty,65bowlswereusedtoservehotfood:soup,riceandchicken.Each bowlofriceservedtwoguests,eachbowlofsoupservedthreeguests,andeach bowlofchickenservedfourguests.Howmanyguestswerepresentatthedinner? (Weassumethatallguestsatethefullmeal:soup,riceandchicken) 2.BillGatesoffersyouajobforonemonth.Hegivesyouachoiceofoneofthe twopossiblesalaryschemes:youcanreceiveeitherasumof$10,000adayfor eachdayofthemonth(includingweekends),oryouwillreceiveyourpayment accordingtothefollowingformula:1centforthefirstday,2centsforthesecond day,4centsforthethirdday,8centsforthefourthdayetc.Whichpayment wouldyouchooseandwhy? 3.OnMonday,aFedExdeliverytruckmadethefollowingsuccessivetrips,starting inthemorningfromitsbase:145kmtotheeast,then175kmtothewest,then20 kmtothewest,then43kmtotheeast. Illustratethetripsofthetruckonthenumberline(wherewillyouputthebase?). Useyourdiagram(andthecalculationsrequired)toanswerthequestionsbelow: (a)Attheendofthefourthtrip,isthetruckeastorwestofhisbase? (b)Howfarmustthetruckdrivetoreturntoitsbase? 4.Numbertrick: (a)Thinkofanumberbetween1and50.Writeitdown.Doublethisnumber.Add20 totheresult.Nowadd6.Subtract17.Subtract9.Divideby2.Whatisthe result?Tryitagain,startingwithanothernumberbetween1and50.Whatisyour answernow? (b)Willthisprocedurealwayswork?Let’sproveit!Startingwith“Letn=the numberbetween1and50”,writeasingleexpressionfortheoperationsdescribed in(a)(intermsofn),rememberingorderofoperations.Remembertobe mathematicallycorrectineverythingyouwrite!Nowsimplifythatexpressionand commentonwhatyoufind.

Answer 1

1每个人都要喝soup,riceandchicken,用(1/2+1/3+1/4)=13/12个碗,65个碗可供:65*12/13=60个人用
2第1种的收入是10000*30=300000元
第2种是等比数列的和=(2^30-1)/100,(首项是1,公比是2,除100是把分化为元),结果远远大于第1种,所以选第2种
3往东用+号表示,往西用-号表示:
[phone]+43=-7
a在西面
b7KM
4假设你想的数是X,Doublethisnumber(2X).Add20
totheresult.Nowadd6.(2X+20+6=2X+26).Subtract17.Subtract9.(2X+26-17-9=2X).Divideby2.(2X/2=X).theResultISX(THESAME)