题解 | #求平均年龄#
求平均年龄
https://www.nowcoder.com/practice/ca319fdb02714994850cc631d76f5547
#Python版代码
n = int(input())
print('%.2f' % (sum(eval(input()) for _ in range(n)) / n))
#或者
from statistics import mean
print('%.2f' % mean(eval(input()) for _ in range(int(input()))))