某班准备从5名游泳队员中选择4人组成接力队，参加学校的4×100m混合游泳接力比赛。 5名队员4种泳姿的百米平均成绩如下表，问应如何选拔队员组成接力队？-Classes to prepare a swim team from the five-member Select 4 relay team, participated in the School of the 4 × 100m relay swimming race mixing. Five members of the four kind

某班有N个学生，已知他们参加某次考试的成绩（0~100间的整数），求全班同学的平均成绩。-A class is to have N students, known as their new the result of the examination (0 to 100 between integer),for the whole class average scores.