Question

3. Pat has 12 books he plans to read during the school year. He decides to take 4 of these books with him while on winter break vacation. He decides to take Harry Potter and the

Sorcerer’s Stone as one of the books. In how many ways can he select the remaining 3 books?

Answer 1

165

Explanation:

Data provided in the question:

Initial Number of books available to read = 12

Number of books Pat took with him = 4

Since, 1 book has already been selected

Therefore,

The number of choices left = 12 - 1 = 11

Number of remaining books to be chosen = 3

Number of ways of choosing the remaining books = ¹¹C₃

=
`(11!)/(3!(11-3)!)`

=
`(11*10*9*8!)/(3*2*1(8!))`

= 990 ÷ 6

= 165