def format_time(t: float) -> str:
    """
    Format a time duration in a readable format.
    
    :param t: The duration in seconds.
    :return: A human readable string.
    """
    hours, remainder = divmod(t, 3600)
    minutes, seconds = divmod(remainder, 60)
    return '%d:%02d:%02d' % (hours, minutes, seconds)