### Brain Teasers

# Psychopets

In a small country town, some of the pets were confused about their identities. 20% of the cats thought they were dogs while 20% of the dogs thought they were cats. The local veterinarian psychiatrist took a survey and found that 40% of all the cats and dogs thought they were cats. What percentage of all the cats and dogs were really cats?

### Hint

Paws up all those who think they are a cat!### Answer

Let there be x cats and y dogs.80% of x + 20% of y = 40%(x+y)

40% of x = 20% of y

2x = y

The number of dogs is double the number of cats.

Say there are 100 cats and 200 dogs. 33 1/3% of all of the animals are really members of the meow generation!

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## Comments

Did I miss something?

I liked it, even though it was easy.

Mar 14, 2003

80% of the cats THOUGHT they were cats(?).

sure they did, and they were right, too!

Mar 14, 2003

Sorry, but I just don't get it. What

does it matter what they think they are?

To answer the question, it only

matters what they actually are but

there isn't enough info to help us answer

the question..? I'm missing something...

does it matter what they think they are?

To answer the question, it only

matters what they actually are but

there isn't enough info to help us answer

the question..? I'm missing something...

tomcat, maybe you are missing something... like maybe you think you're a tomDOG?

Look at the hint: Paws up all those who think they're a cat! How many animals will lift their paws?

80% of x + 20% of y

which also happens to equal 40% of the total number of animals, i.e.

40% of (x+y)

put differently:

0.8x + 0.2y = 0.4(x+y)

so: 0.4x = 0.2y

2x = y

So what percentage are cats? Simply the number of cats divided by the total number of animals, or:

x / (x + y) = x / (x + 2x)

= x / (3x)

= 1/3

= 33 and 1/3 %

Look at the hint: Paws up all those who think they're a cat! How many animals will lift their paws?

80% of x + 20% of y

which also happens to equal 40% of the total number of animals, i.e.

40% of (x+y)

put differently:

0.8x + 0.2y = 0.4(x+y)

so: 0.4x = 0.2y

2x = y

So what percentage are cats? Simply the number of cats divided by the total number of animals, or:

x / (x + y) = x / (x + 2x)

= x / (3x)

= 1/3

= 33 and 1/3 %

But, Cats are cleverer than dogs, so they may have been faking it all along.

Great teaser I've got headache now!!!

Great teaser I've got headache now!!!

Thought is often used in the context of "contrary to fact". Here eigthy percent of the cats "knew" they were cats.

I gues none of you sre in high school or even middle school for that fact and have never taken algebra so I'll leave it at it was a good riddle and I liked it although i really shouldn't be thinking on the weekend

im in 7th grade thanks(2nd yr of middle school) ne ways i thought the teaser was pointless and not very good. it was more of a math problem thn a teaser!

That would've beeneasy back in high school before my head got knkocked silly and any bit of math knowledge I previously had has left me. Which is a very bad thing in college.

You can count my dog as one of those who thinks she's a cat! Great math exercise!! I loved it!

vetrinarian = veterinarian

How did you get from the first equation to the second. I got .4x = -.2y. The whole math is done wrong and to much was assumed .

That was hard and confusing. That was an ok teaser

This was the hardest and stupidest brain teaser. I am in 8th grade and taking Algebra. Who wants to do math on the weekend anyway?

i am in 8th grade too, and i didnt get it. I'm in Algebra. I did it the wrong way though... i thought both the total amounts of dogs and cats had to be the same number. Dumb me!!!

ok well lets see here..im not any math brainiac..so for all of you people that are to good for this little brain teaser must be

Although i'm not a math person i understood the question and after reasearching a little i found the answer

Although it was a rather easy teaser, it was fine as far as teasers go. I don't understand all the issues people are having with this simple problem.

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