<PRE><B>Question 925983</B>
let as assume 4 large books as 1 unit and  3 medium- size book as another unit and 2 small books as one more unit
these 3 units can be arranged in  3! ways
first unit consist of 4 large books. these books can be internally arranged in 4! ways
second unit consist of 3 medium sized books. these books can be internally arranged in 3! ways
third  unit consist of 2 small books. these books can be internally arranged in 2! ways

Total no of ways  =  3! * 4!*3!*2!
3 !  = 3x2x1 = 6
4!~=4x3x2x1 = 24
2! = 2x1 =2
 result  =  3! * 4!*3!*2! 
          = 6*24*6*2
          =1728</PRE>