#int(input())
#map(int, input().split())
#list(map(int, input().split()))

N = int(input())

T = [0] * N
for i in range(N):
    # T[i] = list(map(float, input().split()))
    T[i] = input().split()

for i in range(N):
    for j in range(3):
        s = T[i][j]
        T[i][j] = int(s[:-3]) * 100 + int(s[-2:]) * 1

def S(v, t, m, l):
    v *= 1000 / 3600
    return (v * t * 20 * m) + (v * v) - (l * 20 * m * 10 ** 4)


# print(T)

for i in range(N):
    t = T[i][0]
    m = T[i][1]
    l = T[i][2]
    # print(t, m, l)

    vmax = 52000000
    vmin = 0

    while vmax - vmin > 1:
        h = (vmax + vmin) // 2
        if S(h, t, m, l) > 0:
            vmax = h
        else:
            vmin = h

    # print(format(int(vmin*100)/100, ".2f"))
    # print(vmin)
    # print(vmin)
    vmin //= 100

    c, d = divmod(vmin, 100)
    print(str(c) + "." + format(d, "02d"))