GWD管卫东GMAT第7套题数学第21题求讲解谢谢正确答案是E我觉得C……
Q21:
TheaterMhas25rowswith27seatsineachrow.Howmanyoftheseatswereoccupiedduringacertainshow?
(1)Duringtheshow,therewasanaverage(arithmeticmean)of10unoccupiedseatsperrowforthefront20rows.
(2)Duringtheshow,therewasanaverage(arithmeticmean)of20unoccupiedseatsperrowfortheback15rows.
A.Statement(1)ALONEissufficient,butstatement(2)aloneisnotsufficient.
B.Statement(2)ALONEissufficient,butstatement(1)aloneisnotsufficient.
C.BOTHstatementsTOGETHERaresufficient,butNEITHERstatementALONEissufficient.
D.EACHstatementALONEissufficient.
E.Statements(1)and(2)TOGETHERareNOTsufficient.