#include <bits/stdc++.h> 
using namespace std;
using ll =long long;
#define all(v) v.begin(),v.end()
 #define rep(i,a,b) for(int i=a;i<b;i++)
#define rrep(i,a,b) for(int i=a;i>=b;i--)

ll INF=2e18;

void solve() {
double p;
ll K;
cin>>p>>K;


vector<double> dp(K+1);
dp[1]=1;
for(ll i=2;i<=K;i++) {
  dp[i]=p+(1-p)*(1+dp[i-1]);
}

cout<<fixed<<setprecision(10);
cout<<dp[K]<<endl;

}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  ll t;cin>>t;
  for(ll i=0;i<t;i++) {
    solve();
  }

}