Question 1155685
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<pre>

The number of all quadruples of 4 numbered balls, randomly chosen from 50 numbered balls is

    {{{C[50]^4}}} = {{{(50*49*48*47)/(1*2*3*4)}}} = 230300.


Of them, ONLY ONE group of balls is winning.


So the probability to win is  {{{1/230300}}}.


In all other  230300-230299 cases the gamer loses.


Therefore. math expectation of the game is  {{{50000/230300 - 5}}} = -4.78 dollars.


So, if you play this game MANY TIMES, you should expect to lose  4.78 dollars in each game, as average.
</pre>

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The analysis is completed.


For your safety, DO NOT PLAY THIS GAME (!)




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<U>Comment from student</U>: can you show the steps on how to calculate the expected value, pls?!
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<U>My response</U>.


Look into this Wikipedia article


https://en.wikipedia.org/wiki/Expected_value


and read couple of lines in the section "Definition. Finite case".