野餐趣题
100studentsgatheratapicnic(野餐).85ofthemcarryakite,80ofthemhaveachocolate;75ofthemhavebread;and70ofthembringabag.Ofcourse,someofthemhavealloftheabove(以上都有):kite,chocolate,breadandbag.Ofthese100students,whatistheleastpossiblenumber(最小的数字)whohavealloftheabove?
一百个同学去参加野餐,其中85人带了风筝,80人带了巧克力,75人带面包,70个人带背包,当然,有的人上述东西全带了.请问至少有多少人全部都带了呢?