I thought it was a great idea to create a puzzle game but I can't work out how to give a different score for each answer. For example if there are 3 doors and the player selects the correct door they get 5 points but if they select the wrong door they lose 5 points. I have tried a "IF" command but the score won't change

I'll check in the morning, but you should be able to add an increase score by 'x' amount for their choice. Also, there is a decrease player score script to use for decreasing the player score.

Open blue door --> increase score script
Open red door --> decrease score script

I hope I'm understanding your question correctly.

There is a tutorial here:
http://docs.textadventures.co.uk/quest/score_health_money.html

(The money section is for Quest 5.7, which is not out yet, so the tutorial is not linked from anywhere yet)

thank you both for your help. As you can see I've been busy testing it out