[Archive!] Pure mathematics, physics, chemistry, etc.: brain-training problems not related to trade in any way - page 515

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Mathemat:

There are two white, one blue and one red balloon.

Petya has guessed a colour.

Vasya tries to guess the given colour at random. What is the probability that Vasya will guess?


There is one colour out of three. It doesn't matter how many balls there are - the colour is chosen. If Vasya picks the first one out of the three, the probability of guessing it is 1/3. But I don't understand, what's the trick of the game? Is it that the number of balls is mixed in with the number of colours, to confuse them?
 
No, the number of balls is important. But the answer, it seems to me, is still close to 1/3, although not exactly equal.
 
Mathemat:

There are two white, one blue and one red balloons.

Petya has puzzled a colour.

Vasya tries to guess the given colour at random. What is the probability that Vasya will guess?


It depends on what he gets for it. Quite seriously, by the way ...
 

The situation will be different if Vasi has the balls in an opaque bag and that bag serves as a random colour generator. Then the probability changes. 2 white + 1 blue and + 1 red = 4 balls. The probability of white falling out = 2/4 = 1/2 = 50%. Probability of guessing blue = probability of guessing red = 1/4 = 25 per cent.

So what's the point of the problem? It's an elementary problem.

 
drknn:

The situation will be different if Vasi has the balls in an opaque bag and that bag serves as a random colour generator. Then the probability changes. 2 white + 1 blue and 1 red = 4 balls. The probability of white falling out = 2/4 = 1/2 = 50%. Probability of guessing blue = probability of guessing red = 1/4 = 25 per cent.

So what's the point of the problem? It's an elementary problem.

Take your time, drknn. Justify your reasoning.
 
drknn:

The situation will be different if Vasi has the balls in an opaque bag and that bag serves as a random colour generator. Then the probability changes. 2 white + 1 blue and + 1 red = 4 balls. The probability of white falling out = 2/4 = 1/2 = 50%. Probability of guessing blue = probability of guessing red = 1/4 = 25 per cent.

So what's the joke of the problem? It's an elementary problem.


So they're in the opaque one :)
 

X^X^ ... ^X =2.7182818285

Solve the equation.

 
Is it an infinite sequence of erections? If so, it's elementary (subject to convergence, of course; but it already is).
 

Top down. Brackets from top to bottom

 
Well, see the answers in the private box.
1...508509510511512513514515516517518519520521522...628
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