Question 1202099: A shelf has books with different colored covers; 5 are blue; 6 are red; 1 is orange; 3 are white and 1 is blue and white. What is the probability of choosing a book that has either blue or white on it's cover?
Found 2 solutions by ikleyn, Edwin McCravy:
Answer by ikleyn(52886)   (Show Source):
You can put this solution on YOUR website! .
A shelf has books with different colored covers; 5 are blue; 6 are red; 1 is orange; 3 are white
and 1 is blue and white. What is the probability of choosing a book that has either blue or white on it's cover?
~~~~~~~~~~~~~~~
"Either blue or white" means "blue or white, but not both at the same time".
Therefore, the calculation is as follows
P =  =  =  . ANSWER
Solved.
" Either . . . or " is called " OR exclusive " as opposite to simple " or ", which is " OR inclusive ".
///////////////////
Edwin, I read your post attentively.
As a well-mannered person, I should thank you for your valuable addition to my post.
But I do not catch an idea, for which reason it was written and posted in connection with my post.
It would be more appropriate to place your writing as a section "on using words either - or"
somewhere in Encyclopedia of English everyday language and everyday communications.
In my post, I did not have intention to teach the reader on using "either-or" in everyday communication,
which is OBVIOUS from the text.
My goal was to solve the problem, to explain the solution, and to teach the reader a bit
on using these words "either-or" in Math.
I was very surprised to read your comment to my post.
In English, there are about one million words, according to some sources,
and similar comment, as in your post, can be written to each of these
million words (and to myriads of their combinations), but will it make sense
to write and to post such additions to each word (and their combinations) at this forum ?
Will it make sense to provide a reader with information, which he did not request ?
Sorry, I did not catch your idea . . .
At this forum, really there are tons of posts, where the meaning is unclear.
But in your post, you try to polish something, which is ABSOLUTELY clear even without your polishing.
It reminds me of a doctor who treats a patient for a non-existent disease. 100% analogy.
Folk wisdom says: "do not repair things that work".
\\\\\\\\\\\\\\\\\\\\
There is a teachers' golden rule:
- when you teach students, tell them truth, only truth, but not all the truth.
If some madman teacher will tell ALL THE TRUTH to students,
then the probability is high that the students will become idiots.
Answer by Edwin McCravy(20064)  (Show Source):
You can put this solution on YOUR website!
Ikleyn above says " Either . . . or " is called " OR exclusive " as
opposite to simple " or ", which is " OR inclusive ".
She is correct that "simple 'or'" (without "either") in mathematics and logic is
USUALLY taken to mean "inclusive or". However in everyday speech this rule is
by no means adhered to.
The English language is not at all always consistent concerning whether
"either...or" means "exclusive or" or "inclusive or"
Suppose I have a pen but no pencil. Then suppose someone asks me:
"Do you have a pen or a pencil?"
Of course, I would answer "Yes".
[I would also answer "Yes" if I have a pencil but no pen.]
If the person asked me:
"Do you have either a pen or a pencil?"
I would also answer "Yes".
Now, suppose I have BOTH a pen and a pencil. Then suppose someone asks me
"Do you have a pen or a pencil?"
Of course, I would answer "Yes".
If the person asked me:
"Do you have either a pen or a pencil?"
I would also answer "Yes".
So I would answer "Yes" no matter how many or which writing implement (or
implements) I had. I would also answer "Yes" whether the person said "or"
or "either...or".
It is unfortunate that the rules of the English language are not clear
concerning how to express "exclusive or" and how to express "inclusive or".
The use of "A and/or B" always means "inclusive or". "A or B but not both"
always means "exclusive or".
It is important for students AND TEACHERS to be very careful to state exactly
what they mean, and to be aware of inconsistencies in the English language.
Edwin
|
|
|
