I am having problems with trying to solve this riddle therefore I am looking for help. The situation is as follows:
At a semiconductor laboratory in Hsinchu a security guard caught five technicians accessing a high level security area reserved for the most trusted scientists working in a new integrated circuit for an upcoming computer. However the security film is not very clear and the security team can only be sure that four out of five technicians have the access key card to enter the chipset room.
During interrogation the security team deduces that two of the technicians are lying and the other are telling the truth.
The answers given by the laboratory technicians were as follows:
Audrey: Gwendolyn does not have an access credential.
Dorothy: I was entrusted an access key.
Marina: Hannah has an access key.
Gwendolyn: Audrey is lying.
Hannah: Dorothy is telling the truth.
Based on this information. Which of the technicians does not have access to the chipset room?
Normanlly I would try to show some effort into this but here I'm stuck at the very beginning. In my findings the only I could come up with was the problem looks to be Knights and knaves kind which is related to logic.
But in this case there are five individuals, hence the number of possible combinations would mean $2^5=32$ which raises a flag to me as $32$ combinations seems too big to make it a practical approach to try one by one.
Therefore I need help into finding a solution or a method which would ease and simplify or solve this problem easily.
Can somebody help me with this? I'm not very knowledgable with this type of problem. It would help me a lot to visualize what's going on if the proposed solution would include some sort of table or grid so I could identify the concluded result.