boksana wrote:

There are 5 Rock songs, 6 Pop songs, and 3 Jazz. How many different albums can be formed using the above repertoire if the albums should contain at least one Rock song and one Pop song?

A. 15,624

B. 16,384

C. 6,144

D. 384

E. 240

I have solved this with a bit different approach. Can someone help me where I went wrong in this approach..

We need atleast one Rock song => 5c1 ways to select one rock song

We need atleast one Pop song => 6c1 ways to select one pop song

In the remaining 12 songs, we can take any number of songs ranging from 0 to 12 => 2^12

All put together , we have 5c1 * 6c1 * 2^12

But none of the options match this. Where did I go wrong..