[Community Puzzle] Kiss the girls

Puzzles
#21

How did you get 7? Can you explain me please?

#22

I was getting 7 because I was doing the calculation incorrectly. I was naively just adding up the cumulative risk, which caused it exceed the limit more quickly.

#23

what should you do then

#24

Somebody above pointed out to me that if you flip a coin twice in a row, the possibility of hitting the same thing twice is not 100% (i.e. 50% + 50%). It is actually only 25% as there are only four possible outcomes.

There is a formula for calculating combined probabilities.

#25

letā€™s supposed the events :

  • A : catching monkeypox from the girl A
  • B : catching monkeypox from the girl B

the Probability of catching monkeypox from two girls (A,B) is :

P(A U B) = P(A) + P(B) - P(A āˆ© B)   (1)

Where :

  • P(A) = min(x_A,y_A)/(x_AĀ² + y_AĀ² + 1)
  • P(B) = min(x_B,y_B)/(x_BĀ² + y_BĀ² + 1)
    and since the event A is distincts from the event B then we can say that :
    P(A āˆ© B) = P(A) * P(B) (2)
  1. to calculate the Probability of Three girls (letā€™s say A,B ,C) : ( using (1) and (2) )
 P(AUBUC) = P((AUB) U C)
          = P(AUB) + P(C) - P(AUB) * P(C)

and so one(recursively) until you find the solution

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#26

The great thing about this puzzle is, if you didnā€™t know how to solve it going in, youā€™ve learned something that will fundamentally change the way you look at the world.

1 Like