#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    int n, m, k;
    cin >> n >> m >> k;
    int cardsPlayer = n / k;
    double maxCard;
    int jokerMax = min(m, cardsPlayer);
    maxCard = ceil((m - jokerMax) / (k - 1.0));
    if (jokerMax - maxCard > 0)
      cout << jokerMax - maxCard << endl;
    else
      cout << 0 << endl;
  }
  return 0;
}
