In a Question paper there are 4 subjects. Each subject has has 5 question sets with each subject having one single question set that is the toughest of all. What is the total number of ways in which a candidate will not get all the four toughest question sets? Choose one:	A) 19	B) 85	C) 120	D) 624	E) 1024
A candidate can get a question set in 5*5*5*5=5^4 number of ways (each aubject has 5 question sets and we have total of 4 subjects). Now, out of these cases there will be only one case when the candidate got all the four toughest question sets. Therefore the total number of ways in which a candidate will NOT get all the four toughest question set is is 5^4-1=624.   Answer: 624.
<result>D</result>
In a Question paper there are 4 subjects. Each subject has has 5 question sets with each subject having one single question set that is the toughest of all. What is the total number of ways in which a candidate will not get all the four toughest question sets?