Question

How many different sections of 4 books can be made from 10 different books, if two particular books are always selected?

Answer 1

According to the given question we must always select two  particular books so we can select those two books in one way.
Now we are left with 8 books out of these eight books we can select any 2 books in 8C2 ways .
so the total no of ways of selecting books = 8C2*1=8C2 ways = 28 ways 

Answer 2

I m not sure but I think it is 28