Question

how many ways can a group of 3 students be chosen from a class of 30

Answer 1

Do you know about combinations?
You choose 3 from 30, so that makes 30 choose 3 or 30c3

Answer 2

\(\Large \color{MidnightBlue}{\Rightarrow nCr = {n! \over (n - r)!*r!} }\)

Here,

\(\Large \color{MidnightBlue}{\Rightarrow 30C3 = {30! \over (30 - 3)!*3!} }\)

Answer 3

what is !

Answer 4

Here, we have:


\(\Large \color{MidnightBlue}{\Rightarrow {30 * 29 * 28 * 27! \over 27! * 3!} }\)

We cancel out the 27!

\(\Large \color{MidnightBlue}{\Rightarrow {30 * 29 * 28 \over 3 * 2} }\)

Answer 5

! means factorial.

Answer 6

For example, 4! means 4 * 3 * 2 * 1
7! means 7 * 6 * 5 * 4 * 3 * 2 * 1
And just like that.

Answer 7

4060?

Answer 8

Yes. 4060.

Answer 9

awsome

Answer 10

hehe