# Eight cards are on the table.

Discussion in 'General Philosophy' started by Speakpigeon, Feb 14, 2019.

1. ### SpeakpigeonValued Senior Member

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Eight cards are on the table.

Each card has one capital letter (e.g. F, G, X etc.) on one side, and one number (below 10, e.g. 3, 7, 8 etc.) on the other side.

At the moment, the cards show K, -4, 7, P, R, 0, 5, and 2.

What are the cards you really need to turn over to determine whether or not it's true of all the cards on the table that if there is a vowel on one side, then there is an even number on the other side.

EB

3. ### billvonValued Senior Member

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21,476
For even numbers? All of them. The last card could always have an even number.
For vowels? All of them. The last card could always have a vowel.

Are you leaving something out of your explanation, like each number or letter is only used once in a run of cards?

5. ### BaldeeeValued Senior Member

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You would only need to turn over the 7 and 5.
You don't need to turn over the K, P, and R, because the requirement only concerns cards with a vowel.
You don't need to turn over the even numbers, because the requirement says nothing about non-vowels not also being allowed to have an even number on the other side.

You therefore only need to turn over the 7 and 5 because only the numbers on the other side of these cards can possibly show that the requirement is not being fulfilled.

7. ### gmilamValued Senior Member

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3,455
Turn over all the cards that are currently showing numbers.

EDIT: On further examination, Baldee is correct, we only need to confirm that 5 & 7 are not vowels.

8. ### SarkusHippomonstrosesquippedalo phobeValued Senior Member

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10,155
Cue speakpigeon ranting about how you are not sticking to the OP by letting someone else's answer sway you.

Anyhoo, 5 and 7.
Reasons already given by my inestimable colleague Baldeee.

9. ### RainbowSingularityValued Senior Member

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?

Last edited: Feb 15, 2019
10. ### James RJust this guy, you know?Staff Member

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Well, that was a quick thread.

11. ### SpeakpigeonValued Senior Member

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I wanted to have one without having to insult people.
EB

12. ### DaveC426913Valued Senior Member

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You never have to insult people...

13. ### RainbowSingularityValued Senior Member

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i wanted to go back to double check.
this proves that it is impossible

adding minus numbers to the total means the formula is unable to be quantified.

if you had not put minus numbers into the equation with the -4
then a probability would be possible to load as a set value of probability.
but you cant with an infinite range of odd & even numbers below 0

14. ### James RJust this guy, you know?Staff Member

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Huh? -4 is still an even number. There's an infinite number of odd and even numbers greater than zero, too.

15. ### RainbowSingularityValued Senior Member

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whole numbers below 10
all minus numbers are whole ?
and even & uneven ?
infinity ?

i am not good at maths but that is my guess
-4 is even, but there is no total range of limit to even and odd by labeling the bottom level of whole minus numbers to complete the range ...

16. ### James RJust this guy, you know?Staff Member

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38,908
From what you've written, I can't understand what you're objecting to.

Yes, there are whole numbers below 10.
No, all negative numbers are not whole numbers (integers).
Yes, some numbers below ten are even and others are odd.
Infinity doesn't appear to be relevant.
There is no range limit on positive numbers, any more than there is on negative numbers.
The original question does not in any way rely on a lower bound for potential integers on the cards.

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18. ### James RJust this guy, you know?Staff Member

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38,908
I give up. I'm out.

19. ### DaveC426913Valued Senior Member

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RS: clearly, you are looking for some sort of pattern, but I suspect you are over-thinking it.
There is no restriction on what numbers can be applied here. They are simply grouped by odd and even.

20. ### SpeakpigeonValued Senior Member

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OK, now, suppose no card has a vowel on it, either side.

How do you explain that we say it's true that if there is a vowel on one side, then there is an even number on the other side?
EB

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-?
EB

22. ### DaveC426913Valued Senior Member

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I'm not certain we do say that's true.
I'd want to see someone assert it before I try to explain why they might assert it.

23. ### RainbowSingularityValued Senior Member

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?

if you require 2 known values to present a single answer
knowing that there is an infinite number of minus numbers, it makes it impossible.

you cant use infinity and add it to a probability scale to give an answer.
unless your using metaphors of thought and remove all the mathematics.
in which case your terms are not mathematical.

soo this then asks the question
"what is numbers?" answer = dont know = numbers mean nothing
"what is an alphabet?" = an alphabet is how we make sound for words to talk which is not mathematics.

you may as well be saying
i want you to start by imagining infinity.
once you have grasped infinity in your mind, hold it there and tell me when you have because im going to ask you a question about how it works.