Question

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?

Answer 1

Hint:

you have 'b' choices for the first book, b-1 choices for the second book and b-2 choices for the third book

Answer 2

i don't get it

Answer 3

Look up the counting principle and that may help you out

Answer 4

It's not counting as in (1, 2, 3, 4...), it's counting as counting a very large number of items

http://www.regentsprep.org/Regents/math/ALGEBRA/APR1/Lcount.htm

Answer 5

b1*b2?

Answer 6

close, but not quite

Answer 7

Say you pick out 10 books, you would have

10 books for the first choice, 9 for the second, and 8 for third

So you would have 10*9*8 = 720 choices possible

Answer 8

b^3 ?

Answer 9

no

Answer 10

multiply out b, b-1 and b-2

Answer 11

(5b-3)?

Answer 12

no

Answer 13

b(b-1)(b-2) = ???

Answer 14

b^3-3b^2+2b

Answer 15

you got it

Answer 16

thank you!

Answer 17

yw