Assume that the student
has a cup with 12 writing implements: 7 pencils, 4 ball
point pens, and 1 felt-tip pen.
In how many ways can the student select 7 writing implements?

Question

Assume that the student
has a cup with 12 writing implements: 7 pencils, 4 ball
point pens, and 1 felt-tip pen.
In how many ways can the student select 7 writing implements?

anonymous · Answer

This is a combinatorics question. It is $$\left(\begin{matrix}12 \ 7\end{matrix}\right)$$

anonymous · Answer

But I will explain why

anonymous · Answer

You have 12 choose from, and you need 7 things. The order doesn't matter. An element can not be repeated in the set. This is the reason for it

anonymous · Answer

okay thank you!

anonymous · Answer

Do you know the formula to compute it?