3道gmat数学概率排列组合题
1.Onacertaintransatlanticcrossing,20percentofaship’spassengersheldround-tripticketsandalsotooktheircarsabroadtheship.If60percentofthepassengerswithround-tripticketsdidnottaketheircarsabroadtheship,whatpercentoftheship’spassengersheldround-triptickets?A.331/3%B.40%C.50%D.60%E.662/3%2.Thereare8booksonashelf,ofwhich2arepaperbacksand6arehardbacks.Howmanypossibleselectionsof4booksfromthisselfincludeatleastonepaperback?A.40B.45C.50D.55E.603.Thereare8magazineslyingonatable;4arefashionmagazinesandtheother4aresportsmagazines.If3magazinesaretobeselectedatrandomfromthe8magazines,whatistheprobabilitythatatleastoneofthefashionmagazineswillbeselected?A.1/2B.2/3C.32/35D.11/12E.13/14求指教和具体解法已晕==