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?
A 20 B 60 C 120 D 360

Question

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?
A 20 B 60 C 120 D 360

calculusxy · Answer

@agent0smith

agent0smith · Answer

6 choose 3, use the combinations formula, or the button on a calculator.

calculusxy · Answer

I don't know the combination formula neither do  I calculator that has the combinations formula button.

calculusxy · Answer

*neither do I have

agent0smith · Answer

Formula and calculator. http://www.mathsisfun.com/combinatorics/combinations-permutations-calculator.html

calculusxy · Answer

Another problem: I am using my iPad and it doesn't have a Flash Player.

agent0smith · Answer

http://www.mathsisfun.com/combinatorics/images/combinations-no-repeat.png

calculusxy · Answer

How do you compute with the ! sign? And how do you get the 5,4,3,2etc?

calculusxy · Answer

Can you please help me ? @agent0smith @britneyspears

agent0smith · Answer

Factorial sign.

5! = 5*4*3*2*1

calculusxy · Answer

So if there was 3!=3*2*1?

anonymous · Answer

yes

calculusxy · Answer

Can you help me with my question I am really confused and am lost in the middle of the way?

calculusxy · Answer

Is n the original amount and r is the number of selection?

agent0smith · Answer

Yep

calculusxy · Answer

Is the answer 20?

agent0smith · Answer

Yes

calculusxy · Answer

Thank you