Dear Joffm,
Thank you so much, I have gained allot of example, from which I can choose that one that fit to my study. Now, I am working with the platform and become friendly with it. Have a nice time.
With regards;

Hi,
$('#question' + questions).hide();
In my opinion this will not work, as here the {QID} is needed.

On the other side: This approach is simply covered by the "two groups" solution (one visible, one hidden)

Joffm