Question 1155391
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I think the EVERY person familiar with the PROBABILITY notion (definition), who is able, in addition, 
to add one-digit numbers, can solve this problem on his or her own.


Moreover, the notion of Probability is so intuitively clear, that even formal knowledge of the definition is not necessary.


So, if you can not do it on your own, then I only may conclude, that EITHER


<pre>
    You are not familiar with the notion of probability, 
</pre>OR

<pre>
    you don't want to do anything on your own, and only want the tutors make your job instead of you.
</pre>

No one of these arguments is the reason for me to help you.