设80分的有x人比平均分少的总分为 (79-50) + (79-60) * 2 + (79-70)*5 = 112 比平均分多的总分为 (90-79) * 5 + (100-79) + x = 76 + x所以 76 + x = 112x = 112 - 76 = 36所以全班有36 + 1 + 2 + 5 + 5 + 1 = 50 人...