How many ways can you purchase 2 cds if there are 3 to choose from, 4 cassettes if there are 4 to choose from, and 2 dvds if there are 5 to choose from?

60

50

40

30

The concept of combination is very useful in answering the question above. The solution to the problem is presented below. 
 
                                    n = (3C2) x (4C4) x (5C2)

where n is the number of ways the CDs, cassettes and DVDs may be chosen from the given choices.
 
Evaluating the equation, 
 
                                        n = 30

Therefore, the answer is 30.