You have checked out b books from the library, where b is a number greater than 5. You plan to read three of the books and return them at the end of this week. In how many ways can you pick the books you will read first, second, and third?

Question

anonymous · Answer

A. b3 ways 	
  B. (b3 - 3b2 + 2b) ways 	
  C. (b3 - 9b2 + 27b - 27) ways 	
  D. (5b - 3) ways

kropot72 · Answer

There are b choices for the first book, (b - 1) choice for the second choice and (b - 2) choices for the third.
$$\large Number\ of\ choices=b \times (b-1)\times (b-2)=you\ can\ multiply\ out$$

anonymous · Answer

so would it be D?

arindameducationusc · Answer

I guess Not D

kropot72 · Answer

Partially multiplying out, the number of ways is given by$$\large b(b^{2}-3b+2)=you\ can\ multiply\ out$$

anonymous · Answer

Honestly, this makes no sence to me

arindameducationusc · Answer

okay, do you know distributive law?

anonymous · Answer

yes.

anonymous · Answer

I got B. Is that correct?

kropot72 · Answer

Yes, b is the correct choice of answer.

anonymous · Answer

OKay, thank you

kropot72 · Answer

You're welcome :)