N = int(input())
X = list(map(int, input().split()))
M = int(input())

ave = sum(X)/N

memo = 0
for x in X:
    memo += (x - ave)**2
memo = (memo/N)**(1/2)
print(memo)

x = X[M - 1]

ans = 50 + (10*(x - ave)/memo)
print(ans)