Q42. 
There are 5 Rock songs, 6 Carnatic songs and 3 Indi pop songs. How many different albums can be formed using the above repertoire if the albums should contain at least 1 Rock song and 1 Carnatic song? 
A.  $15,624$ 

B.  $16,384$ 

C.  $6,144$ 

D.  $240$ 
Q43. 
A bookshelf can accommodate 6 books from left to right. If 10 identical books on each of the languages $A,B,C$ and $D$ are available, In how many ways can the book shelf be filled such that book on the same languages are not put adjacently. 
A.  $\dfrac{^{40}P_6}{6!}$ 

B.  $10 × 9^5$ 

C.  $\dfrac{^6P_4}{2!}$ 

D.  $4 × 3^5$ 