from collections import deque, defaultdict, Counter
from bisect import bisect_left, bisect_right
from itertools import permutations, combinations, groupby
from heapq import heappop, heappush
import math, sys
input = lambda: sys.stdin.readline().rstrip("\r\n")
def printl(li, sep=" "): print(sep.join(map(str, li)))
def yn(flag): print(Yes if flag else No)
_int = lambda x: int(x)-1
MOD = 998244353 #10**9+7
INF = 1<<60
Yes, No = "Yes", "No"

for _ in range(int(input())):
    N, M, K = map(int, input().split())
    k = -(-K//M)
    ans = 0
    cnt = 1
    for i in range(k):
        n = N-i
        ans += cnt/n*(M-1)/M
        cnt *= (n-1)/n
    ans += cnt
    print(ans)