Melody

This is identical as my last question but i missed one thing.

Ana, Beatriz and Celia are 3 kids they say 3 statements ONLY one of these statements are true.

Beatriz is the oldest     Ana is not the oldest     Celia is not the youngest

Put the 3 kids in order from oldest to youngest! 

Lets look at each one.

Say Beariz is the oldest it true.  

Then Ana is not the oldest is also true but only one statement can be true SO

Beatriz is NOT the oldest

Say Ana is NOT the oldest is true.

We know that Beatriz is not the oldest,  If neither of those 2 are the oldest then Celia must be the oldest.

BUT this would mean that statement 2 and statement 3 are both true and that is not allowed.

Therefore Ana is the oldest

Edits are in red

Say Celia is not the youngest. then Ana is the oldest and Beatriz must be the youngest

Ana is oldest, then Celia , and the youngest is Beatriz

Hi DS

I have not had any problems uploading images.  Are you sure you are doing it correctly?

Sat 28/11/15

1) Music Report #10      Thanks Dbg4thebest       

   http://web2.0calc.com/questions/music-news-report-10

2) Social post:  It is like an great reunion! Me, TitaniumRome and Dragonlance

   http://web2.0calc.com/questions/8-1-7-how-do-i-put-this-in-the-calculator/new#edit

3) Basic fact wioth trigonometry - what does the co stand for in cosine?     Melody

    http://web2.0calc.com/questions/if-3n-1-is-a-perfect-square-show-that-n-1-is-the-sum-of-three-perfect-squares#r1

4) Statistics question from DragonSlayer554.    Thanks  Dragonlance.

    https://web2.0calc.com/questions/math-question-i-m-back

5) Calculus   Thanks Alan

   https://web2.0calc.com/questions/calculus-question_1#r2

6) Proof    Thanks Heureka

    http://web2.0calc.com/questions/if-3n-1-is-a-perfect-square-show-that-n-1-is-the-sum-of-three-perfect-squares#r1

7)  Intuitive problem.  Thanks guests, CPhill and Melody.

     http://web2.0calc.com/questions/please-give-an-intuitive-explanation#r6

8)   Proof    Thanks guys but I would really like another mathematician to look at this one. :/

     This was from last time but I would still like it to be discussed further :/

     https://web2.0calc.com/questions/help_67408

@@ What is Happening?  [Wrap4]   Fri 27/11/15   Sydney, Australia Time 3:35 pm   ♪ ♫

Hello everyone,

My weekend is already beginning but many of you will have to wait another day or so!  :)

We have had some great answers from CPhill, Anonymous4338, buubleman, Geno3141, Heureka, and Dancer04.  Thank you, you are all wonderful.     

Forum Improvement:

We now have an inbox for private messages.  This is great!    Thanks Mr Massow.   

Interest Posts:

If you ask or answer an interesting question, you can private message the address to me (with copy and paste) and I will include it.  Of course only members are able to do this.  I quite likely will not see it if you do not show me.  

1) Call for guests to become members.   Thanks Anonymous4338  :)

Hi guest,      

I appreciate that you offered an answer, I want everyone to participate and I hope that you are not offended by my involvement.  I also hope that you and the asker both learn someting positive from my input here.

In this case it was a necessary for you to state your assumption.

You see, this student, and many others, do not understand that they are solving an equation that must be equal to zero.

SO the most important thing was to teach the student why their question made no sense.

When answerers make assumptions they must state it.  

They may do this just by rewriting the question properly (as they assume it to be) 

OR they may make a song and dance about it like I have here.

BUT either way, the questioner must be told what question you are answering.   

I thought zoka123 would be looking for a general proof.    

Yes, this one looks reallly interesting.   Thanks Geno and Heureka.

I have put it aside for when I have more time. I want to look at both your answers  :)

Yes thank you anonymous4338 and guest,

General thank yous are nice but it is very appreciated if you say thank you on your own question or interest thread.

People like personal thank yous.  It is nice to say thank you, and ask for more clarification if neccessary, every time you recieve an answer.  :)

Thanks 4338 that is really sweet of you :)

This is a mathematics site Mr Banker. Not a finanical site.

Why don't you show some ability and show the derivation of your formula.

I know the derivation has already been done by someone else so you should be able to find it easily enough on the net.

I have seen no evidence that you are capable of deriving it for yourself.