function ToggleAnswerDisplay(id)
{
  if(document.getElementById(id).style.visibility == "hidden")
  {
    document.getElementById(id).style.visibility = "visible";
    document.getElementById(id).style.display = "block";
  } else {
    document.getElementById(id).style.visibility = "hidden";
    document.getElementById(id).style.display = "none";
  }
}