#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef unsigned long long ull;
typedef long double ld;
int dx[8] = { 1, 0, -1, 0, 1, 1, -1, -1 }, dy[8] = { 0, 1, 0, -1, 1, -1, 1, -1 };
const long long mod = 998244353;
const ll inf = 1LL << 60;
const int INF = 5e8;

void solve()
{
    int k;
    ld p;
    cin >> p >> k;
    vector<ld> dp(k + 1);
    for (int i = k - 1; i >= 0; i--) {
        dp[i] = (1 - p) * (dp[i + 1] + 1) + p;
    }
    printf("%.18Lf", dp[0]);
}

int main()
{
    int t;
    cin >> t;
    while (t--)
        solve();
}