Question

of 18 possible books, you plan to take 4 with you on vacation. How many different collections of 4 books can you take?

Answer 1

you are being asked for the number of ways to choose 4 out of 18
written as
\[\binom{18}{4}\] or
\[_{18}C_4\] pr even
\[^{18}C_4\]

Answer 2

compute via
\[\binom{18}{4}=\frac{\overbrace{18\times 17\times 16\times 15}^{\text{4 term}}}{4\times 3\times 2}\]

Answer 3

yes, I am using the formula n! / (n-r)!r!

Answer 4

when I do, I get 1,762,560. that just seems to high

Answer 5

cancel first, multiply last since the answer is a whole number
or just cheat
http://www.wolframalpha.com/input/?i=18+choose+4

Answer 6

you should get 3060 , after all i said and done

Answer 7

thank you all

Answer 8

how about this one 64 numbers draw 6 order doesn't matter, how many combinations?

Answer 9

There are 56 republicans and 42 democrats and 2 independents how many committees could be formed if each one must contain 3 republicans sand 2democrats?

Answer 10

help