import std;

void main () {
    int T = readln.chomp.to!int;
    foreach (_; 0..T) {
        double p;
        int K;  readln.read(p, K);
        auto ans = solve(p, K);
        writeln(format("%.10f", ans));
    }
}

auto solve (double p, int K) {
    double res = 0;

    // i 回目まですべてレアキャラ以外を出す確率 : (1-p)^i
    double not = 1;
    double P = p;

    for (int i = 1; i <= K; i++) {
        if (i == K) {
            res += i*not;
            continue;
        }
        res += i*not*p;
        not *= 1-p;
    }

    return res;
}

void read(T...)(string S, ref T args) {
    auto buf = S.split;
    foreach (i, ref arg; args) {
        arg = buf[i].to!(typeof(arg));
    }
}