Question

Ques. a boy has 4 different boxes and 5 different marbles. in how many ways can he place the marbles in the boxes such that each box has at least one marble ?

Answer 1

put 2 box together and then keep the marble in then

Answer 2

As when 4 marbles fit in 5 boxes with at least one in each box, 
5! = 5* 4* 3* 2* 1= 120____I 
4! = 4* 3* 2* 1= 24_____II 
multiplying I and II, 
120 * 24 = 2880. 
dividing 2880 by each option given, only Op 2(240) and Op 4(36) divides exactly. 
Now taking the product of 4 and 5 = 20. 
dividing 240)and 36 by 20 gives a perfect remainder with  2. 
Therefore, Ans =
--240.