is there a way of a npc asking three questions and depending on the amount of correct answers depends on what information is given as a prize?

for example if they get one question correct they are allowed to pass, if they get two questions correct then they get a hint about the game, if they get three questions right then they are told which items to pick up

How do you want to do it? choosing answers from a menu or input the answers?

inputing answers

It should be something like this:

 msg("first question:")
 answer= GetInput() 
 if (answer="....") {
   counter=counter+1
 }
 msg("secondquestion:")
 answer= GetInput() 
 if (answer="....") {
   counter=counter+1
 }
 msg("thirdquestion:")
 answer= GetInput() 

 if (answer="....") {
   counter=counter+1
 }
 if (counter=1) {
  ...
 } else if (counter=2) {
  ...
 } else if (counter=3) {
  ...
 }