Question

There are 8 books in a shelf that consist of 2 paperback books and 6 hardback books. If 4 books are selected at random without replacement, how many different combinations are there that at least one paperback book is selected?A. 40B. 45C. 50D. 55E. 60

Answer 1

Answer:D

Step-by-step explanation:

This is combination.

If 4 books selected out of eight book in the shelf:

(4 combination 8)= 70

For hardback selection:

Then selection of 4 books out of the hardback, it means there is no paperbach will be:

(4 combination 6)= 15

So , if at least one paperback selected will be : 70-15

That is 55