190-190÷5=190-38=152（瓶）他们至少要买152瓶.【解析】⑴用150空瓶,换30瓶,另余空瓶2个；⑵用30空瓶,换6瓶,另余空瓶2个；⑶用5空瓶,换1瓶,另余空瓶3个；⑷暂借1空瓶,加上其它4空瓶,换回1瓶,喝完还1空瓶.综上,共喝...