program zzn;
var
        n,m,i,j,x,y,z,q:longint;
        a,w:array[1..50,0..50]of longint;
        ans:double;
procedure init;
begin
        assign(input,'path.in');
        reset(input);
        assign(output,'path.out');
        rewrite(output);
        fillchar(a,sizeof(a),0);
        readln(n,m);
        for i:=1 to m do
        begin
            readln(x,y,z);
            inc(a[x,0]);
            a[x,a[x,0]]:=y;
            w[x,y]:=z;
        end;
end;
procedure closef;
begin
        close(input);
        close(output);
end;
procedure dep(xx,bian,ww:integer);
var
        i:integer;
begin
        if xx=y then
         begin
             if ans>ww/bian then ans:=ww/bian;
             exit;
         end;
        for i:=1 to a[xx,0] do
        begin
            dep(a[xx,i],bian+1,ww+w[xx,a[xx,i]]);
        end;
end;
procedure main;
begin
        ans:=maxlongint;
        dep(x,0,0);
        writeln(ans:0:3);
end;
begin
        init;
        readln(q);
        for i:=1 to q do
        begin
        readln(x,y);
        main;
        end;
        closef;
end.