Melody

There are 18  padded chairs around a circular table, and the chairs are numbered from 1  through 18 . How many ways can five people take their seats, so that no two people are adjacent?

let each person have a chair, no number yet, and also take a empty chair to the right, tie the chairs together

now there are 5 'fat' chairs and 8 chairs not used yet.

So that is  13 altogether. 

 the circle part is a little confusing but rotations are not the same as they usually ars so in most respectes this can be thought of as a line

I was thinking  13C5 to choice the people seats times by 5! to order them.     13C5 * 5!

but in this senario chair 18 will never be sat in.

ok now I will put someone specifically in chair 18  and then I will delete that chair and that person from the scenario.

So 17 chairs left and 4 people left

So now I have 4 'fat' people and and 9 cother chair        1 + 4*2 + 9 =18

the people  be arranged in   13C4 * 4! ways

So i think the answer is     13C5*5!  +  13C4 *4! = 154440+ 17160 = 171 600 ways

yea sorry,

None of that makes sense.

You are right, Cosx is definitely not equal to cos(x+30)

Maybe there is more to the question? 

Looks good to me Stereo.  

Give yourself a thumbs up :)

I've answered on th original.

I get 50% also and I think guest's answer was quite well explained.

You sort of did, you voted it up when you first saw it and then voted it down when you decided it was wrong.

Please do not to this, if a person makes a serious attempt to help you you should always thank them with an upvote, as well as a comment.

You are upvoting them for their time, interest and effort. Not necessarily for their correct answer.

Your comments are quite nice although it is more tactful to say "I do not think it is right because ...(give reason).. " Rather than just  "Sorry, it's incorrect"

2. In how many ways can we distribute 7 pieces of identical taffy and 8 pieces of identical licorice to 5 kids such that each kid recieves exactly 3 pieces of candy.

There are 15 peices of candy of 2 types 

I am only going to concern myself with the 7 pieces of Taffy because for each taffy allocation the licorice allocation is automatically set.

Please just post one question at a time. 

1. 3 students are running for a class president in a class of 70 students. How many different vote counts are possible if some student(s) do not vote.

I still do not understand this question.  

You explanation does not make sense to me. Just for starters the question clearly states that 1 or more students DO NOT vote. So it is impossible for 70 students to vote.

If there are 70 students and some do not vote then there can be a maximum of 69 possible votes to count.

Each of the three students can get between 0 and 69 votes, the sum of the 3 votes is obviously 69 or less.

I do not suppose that this is what the question means but it is impossible to know what the intended meaning is.

How do you know? 

You should always give a reason. even if it is just "I put it in the answer box and was told it was wrong"