Ask your own question, for FREE!
Mathematics 20 Online
OpenStudy (calculusxy):

There are 6 books on a reading list. Students must read 3 of the books on the list. In how many different ways can a student select 3 books?

OpenStudy (solomonzelman):

6 nCr 3

OpenStudy (calculusxy):

i dont get that

OpenStudy (solomonzelman):

That means that you are choosing 6 out of 3.

OpenStudy (calculusxy):

so do i use the formula: n! / ( r!(n - r)! )

OpenStudy (solomonzelman):

Yes!

OpenStudy (calculusxy):

may i ask. what does n and r mean?

OpenStudy (solomonzelman):

Here is the calc for you. http://www.calculatorsoup.com/calculators/discretemathematics/combinations.php

OpenStudy (anonymous):

easy you just multiply the number of books total time the required to read 6x3=18 I think

OpenStudy (solomonzelman):

n is number you are choosing from and r is the number you are choosing.

OpenStudy (solomonzelman):

like in your case n=6 and r=3

OpenStudy (calculusxy):

18 is not on the option @Adriana101

OpenStudy (calculusxy):

thank you all!

OpenStudy (solomonzelman):

18?! No no no, this is COMBINATIONS !

OpenStudy (solomonzelman):

You welcome!

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!