n = int(input())

for _ in range(n):
    t,mu,l = map(str,input().split())
    t100 = int(t.replace(".",""))
    mu100 = int(mu.replace(".",""))
    l100 = int(l.replace(".",""))
    ok = 510001
    ng = -1
    target = 36 * 36 * 10 * mu100 * l100
    while abs(ok - ng) > 1:
        mid = (ok + ng) // 2
        if target < 36 * mu100 * t100 * mid + 50 * mid ** 2:
            ok = mid
        else:
            ng = mid
    moji = str(ng/100) + "0"*10
    if 0 <= ng/100 < 10:
        print(moji[:4])
    elif 10 <= ng/100 < 100:
        print(moji[:5])
    elif 100 <= ng/100 < 1000:
        print(moji[:6])
    else:
        print(moji[:7])