Question 1128157
.
The probability under the question is


<pre>
    {{{(20/(12+20))*(12/31)}}} = {{{(20/32)*(12/31)}}}.
</pre>


This formula is self-explanatory.  &nbsp;If you have questions, &nbsp;look into the formula attentively, &nbsp;and then it will tell you everything about itself.


So, &nbsp;my explanations are not required.



To get the number, &nbsp;use your calculator.