#include <bits/stdc++.h>
#include <atcoder/all>
#include <ranges>
using namespace std;
using namespace atcoder;
//loop
#define REP(i, n) for (ll i = 0; i < (ll)(n); i++)
//vector
#define ALL(A) A.begin(), A.end()
#define RV(A) reverse(ALL(A))
#define RALL(A) A.rbegin(), A.rend()
#define SORT(A) sort(ALL(A))
#define RSORT(A) sort(RALL(A))
//input
template<class T> inline void input(T& a) { cin >> a; }
template<class T> inline void input_li(T& a) {for(auto &ob:a) cin >> ob;}
template<class... T> inline void input(T&... a) { ((cin >> a), ...); }
//output
#define Yes(bo)  cout << ((bo) ? "Yes":"No") << endl
#define YES(bo)  cout << ((bo) ? "YES":"NO") << endl
#define yes(bo)  cout << ((bo) ? "yes":"no") << endl
#define Taka(bo) cout << ((bo) ? "Takahashi":"Aoki") << endl
//other
#define pb push_back
#define pf push_front
#define ppb pop_back
#define ppf pop_front
#define sz size
#define is insert
#define ps push
#define tp top
#define ft front
#define pp pop
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0;}
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0;}
//const
#define I_MAX   2147483647
#define I_MIN   -2147483647
#define UI_MAX  4294967295
#define LL_MAX  9223372036854775807
#define LL_MIN  -9223372036854775808
#define ULL_MAX 18446744073709551615
//type
using ll      = long long;
using ull     = unsigned long long;
using ld      = long double;
using Pair    = pair<ll,ll>;
using vll     = vector<ll>;
using mint    = modint998244353;
using mint1   = modint1000000007;
const ll Inf = 1LL << 60;
//debug
#ifdef _DEBUG
    #define debug(x)    cerr << "dbg_var : " << #x << ": " << x << endl
    #define debug2(x,y) cerr << "dbg_var : " << #x << ": " << x  << " "<< #y << ": " << y << endl
    #define debug3(x,y,z) cerr << "dbg_var : " << #x << ": " << x << " "<< #y << ": " << y << " " <<  #z << ": " << z <<endl
    #define debug_v(x)  cerr << "dbg_vect: " << #x << ": "; for(auto v:x) cerr << v << " "; cerr << endl
    #define debug_s(x)  cerr << "dbg_set : " << #x << ": {"; for(auto v:x) cerr << v << ","; cerr << "}" << endl
    #define debug_p(x)  cerr << "dbg_pair: " << #x << "Fir: " << x.first << " Sec: " << x.second << endl
    #define debug_m(x)  cerr << "dbg_map : " << #x << ": "; for(auto Ite1:x)cerr << "key: " << Ite1.first << " : " << Ite1.second << ", "; cerr<< endl
    #define debug_l()   cerr << "======================================" << endl
#else
    #define debug(x)
    #define debug2(x,y)
    #define debug3(x,y,z)
    #define debug_v(x)
    #define debug_s(x)
    #define debug_p(x)
    #define debug_m(x)
    #define debug_l()
#endif
ll getSum(vector<ll> b) {ll res=0;for(auto v:b){res+=v;}return res;}
ll GCD(ll a, ll b) {if (b == 0) return a;else return GCD(b, a % b);}
ll LCM(ll a, ll b) {ll d=GCD(a,b);return (a/d)*(b/d)*d;}
/*zahyou to ka*/
bool poich(ll P,ll Q){return(0<=P&&P<Q);}
bool poich2(ll i,ll j,ll H,ll W){return(poich(j,W)&&poich(i,H));}
vector<Pair> dxy{{1,0},{-1,0},{0,1},{0,-1}};
//https://algo-logic.info/calc-pow/
ll dpow(ll x, ll n,ll mod) {
    ll ret = 1;
    while (n > 0) {
        if (n & 1) ret = ret * x % mod;
        x = x * x % mod;
        n >>= 1;
    }
    return ret;
}
ll chd21(ll N,ll i,ll j){
    return N*i+j;
}
Pair chd12(ll N,ll X){
    return {X/N,X%N};
}
//input
template <class T>
void input_v(vector<T> &vec){
    for(auto &v:vec)cin >> v;
}
vector<ll> MakePrime(long long MAX_N){
    vector<long long> Isprime,Prime;
    Isprime.resize(MAX_N+2,true);
    Isprime[0]=false;
    Isprime[1]=false;
    for(long long i=2;i*i<=MAX_N;i++){
        if(Isprime[i]){
            for(long long j=i*i;j<=MAX_N;j+=i)Isprime[j]=false;
        }
    }
    for(long long i=0;i<MAX_N;i++)if(Isprime[i])Prime.push_back(i);
    return Prime;
}
template<class T>
struct comb{
    public:
    comb():comb(10000000){}
    comb(ll N):A(N,1),B(N,1){
        for(ll i=0;i<N;i++){
            A[i+1]=A[i]*(i+1);
            B[i+1]=1/A[i+1];
        }
    }
    T nCk1(ll n,ll k){
        
        if(n<0||k<0||n-k<0)return (T)0;
        return A[n]*B[k]*B[n-k];
    }
    T nPk1(ll n,ll k){
        
        if(n<0||k<0||n-k<0)return (T)0;
        return A[n]*B[k];
    }
    T nCk2(ll n,ll k){
        T res=1;
        for(ll i=k+1;i<=n;i++){
            res*=i;
        }
        for(ll i=0;i<=n-k;i++){
            res/=i;
        }
        return res;
    }
    vector<T> A;
    vector<T> B;
};
vector<array<ll,2>> totu_cover(vector<array<ll,2>> points){
    vector<array<ll,2>> p=points; 
    sort(p.begin(),p.end());
    ll N=p.size();
    auto func=[&](bool bo){
        stack<array<ll,2>> st;
        queue<array<ll,2>> que;
        ll k=2*bo-1;
        for(ll i=N-1;i>=0;i--){
            que.push(p[i]);
        }
        while(!que.empty()){
            auto v=que.front();
            if(st.size()<2){
                st.push(v);
                que.pop();
            }else{
                auto o=st.top();st.pop();
                auto t=st.top();
                auto[a,b]=t;
                auto[c,d]=o;
                auto[e,f]=v;
                if((f-b)*(a-c)*k>(d-b)*(a-e)*k){
                    continue;
                }else{
                    st.push(o);
                    st.push(v);
                    que.pop();
                }
            }
        }
        vector<array<ll,2>> res;
        while(!st.empty()){
            res.push_back(st.top());
            st.pop();
        }
        return res;
    };
    auto v=func(1);
    auto u=func(0);
    ll vn=v.size(),un=u.size();
    vector<array<ll,2>> ans;
    set<array<ll,2>> cot;
    for(ll i=vn-1;i>=0;i--){
        ans.push_back(v[i]);
        cot.insert(v[i]);
    }
    for(ll i=0;i<un;i++){
        if(!cot.count(u[i])){
            ans.push_back(u[i]);
        }
        cot.insert(u[i]);
    }
    return ans;
}struct Edge {
    long long to;
};
using Graph = vector<vector<Edge>>;
/* LCA(G, root): 木 G に対する根を root として Lowest Common Ancestor を求める構造体
    query(u,v): u と v の LCA を求める。計算量 O(logn)
    前処理: O(nlogn)時間, O(nlogn)空間
*/
struct LCA {
    vector<vector<int>> parent;  // parent[k][u]:= u の 2^k 先の親
    vector<int> dist;            // root からの距離
    LCA(const Graph &G, int root = 0) { init(G, root); }
    // 初期化
    void init(const Graph &G, int root = 0) {
        int V = G.size();
        int K = 1;
        while ((1 << K) < V) K++;
        parent.assign(K, vector<int>(V, -1));
        dist.assign(V, -1);
        dfs(G, root, -1, 0);
        for (int k = 0; k + 1 < K; k++) {
            for (int v = 0; v < V; v++) {
                if (parent[k][v] < 0) {
                    parent[k + 1][v] = -1;
                } else {
                    parent[k + 1][v] = parent[k][parent[k][v]];
                }
            }
        }
    }
    // 根からの距離と1つ先の頂点を求める
    void dfs(const Graph &G, int v, int p, int d) {
        parent[0][v] = p;
        dist[v] = d;
        for (auto e : G[v]) {
            if (e.to != p) dfs(G, e.to, v, d + 1);
        }
    }
    int query(int u, int v) {
        if (dist[u] < dist[v]) swap(u, v);  // u の方が深いとする
        int K = parent.size();
        // LCA までの距離を同じにする
        for (int k = 0; k < K; k++) {
            if ((dist[u] - dist[v]) >> k & 1) {
                u = parent[k][u];
            }
        }
        // 二分探索で LCA を求める
        if (u == v) return u;
        for (int k = K - 1; k >= 0; k--) {
            if (parent[k][u] != parent[k][v]) {
                u = parent[k][u];
                v = parent[k][v];
            }
        }
        return parent[0][u];
    }
    ll getdist(int u,int v){
        return dist[u]+dist[v]-2*dist[query(u,v)];
    }
};
ld ans(ll N,ll M,ll K){
    //例外をうまいこと処理してこう。
    //N==1の時、M個からK個選んで特定のやつを含まない確率は？
    //M個からK個選んだ時分のM-1個からK個選んだ時=(M-1)!*(M-K)!/(M!*(M-K-1)!)
    if(N==1){
        return max((M-K)/(ld)(M),(ld)0.0);
    }
    ld res=0;
    //甘味があった時
    ll eaten=1;
    eaten+=M*(N-1);
    if(eaten<K){
        res+=(M-1)/(ld)(N*M)*ans(1,M-1,K-eaten);
    }else{
        res+=(M-1)/(ld)(N*M);
    }
    //甘味がなかった時
    eaten=M;
    if(eaten<K){
        res+=(N-1)/(ld)(N)*ans(N-1,M,K-eaten);
    }else{
        res+=(N-1)/(ld)(N);
    }
    return res;
}
void solve(){
    ll N,M,K;cin >> N >> M >> K;
    cout << fixed << setprecision(15) << ans(N,M,K) << endl;
}
int main(){
    ll T=1;cin >> T;
    while(T--){
        solve();
    }
    return 0;
}