Posted by **Genie_math** on Wednesday, October 3, 2012 at 9:01pm.

There are eighteen guard posts. How many ways can 25 not indistinguishable (That is, they are distinguishable.)guards be distributed to the guard posts, so that no post is empty?

Try - (25 choose 18) ??

- Discrete math -
**Reiny**, Wednesday, October 3, 2012 at 9:17pm
Think of it this way:

Every time all the 18 posts are filled, there will be a set of 7 guards left out.

So the question becomes, how many set of 7 from 25 can we find, which is

C(25,7) or C(25,8) , both yield the same answer.

BTW, your clarification in brackets is a contradiction

you probably meant to say

((That is, they are NOT distinguishable.)

## Answer This Question

## Related Questions

- criminal justice - After some recent incidents involving guard mistreatment of ...
- Economics/Marginal Analysis - 21st Century Electronics has discovered a theft ...
- TSU - Twenty-first century electronics has discovered a theft problem at its ...
- Economics - 21st Century Electronics has discovered a theft problem at its ...
- Math-6-grade (Anonymous) - Sorry Anonymous that I deleted your post by mistake, ...
- Math help - How many squares in this figure? (1 point) 4.) 15 5** 20 10** ...
- economics marginal cost analysis - Vaska Electronics has discovered a theft ...
- managerial economics - Twenty first century electronics has discovered a theft ...
- Math - Thomas puts fence posts from one end of a field to the other, equal ...
- criminal justice - hi, I just need some ideas in how to make a SOP Standard ...

More Related Questions