v1, v2, v3, s = map(int, input().split())
s1 = v1*300
s2 = v2*600
s3 = s - (s1 + s2)
if s <= s1:
    print("{0:.6f}".format(s/v1))
elif s <= (s1+s2):
    print("{0:.6f}".format(s1/v1+(s-s1)/v2))
else:
    print("{0:.6f}".format(s1/v1+s2/v2+(s-s1-s2)/v3))