program tju1172;
const
  size=100;
var
  a,b:array[0..size,0..size]of real;
  t,u,k,l,i,j:longint;
  pa,pb:real;
procedure init(n:byte);
  begin
    for i:=0 to n do begin
      a[n,i]:=1;b[n,i]:=1;
      a[i,n]:=0;b[i,n]:=0;
    end;
  end;
begin
  read(t);
  for u:=1 to t do begin
    read(i,j,k,l);

    pa:=i/100;pb:=1-j/100;
    init(l);
    for i:=l-1 downto 0 do
      for j:=l-1 downto 0 do begin
        a[i,j]:=pa*a[i+1,j]+(1-pa)*b[i,j+1];
        b[i,j]:=pb*a[i+1,j]+(1-pb)*b[i,j+1];
      end;

    pa:=a[0,0];pb:=b[0,0];
    init(k);
    for i:=k-1 downto 0 do
      for j:=k-1 downto 0 do begin
        a[i,j]:=pa*b[i+1,j]+(1-pa)*b[i,j+1];
        b[i,j]:=pb*a[i+1,j]+(1-pb)*a[i,j+1];
      end;

    writeln((a[0,0]+b[0,0])*50:0:1);
  end;
end.