Hello Everyone!

I just want to check something here...

Say we have a set $\displaystyle E = {a_1, a_2, \cdots a_n}.$

And we want to get all the subsets of size $\displaystyle k$ and of size $\displaystyle p$ call this set of subsets $\displaystyle S$

So is $\displaystyle |S| = C_n ^k + C_n ^p$??

Thanks for your help