Shall any one tell me!

hello, guys will any one just inform me why is the case study exam format used?

Hi Arnold it is not case study format , but it is testlet exam format.
And the Testlet exam format makes use of case studies that more accurately simulate what Microsoft Certified Professionals do on the job. A case study model also allows us to test the candidate's ability to analyze and synthesize information to make decisions.
I feel this is too sufficient to clear your query.

Hi, buddy thanks for your notes on testlet exam format. Now I have developed a clear idea on this concept.

For demo type questions I have one query, are points deducted in the demo for incorrect answers?
Will any one just help me to clear this problem?

No. Points are not deducted for incorrect answers; if you answer incorrectly, you will simply not earn the credit associated with answering correctly.

Oh, now I have got the point on wrong answer.