Question 1148222
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Note that the total number of marbles in the box is  2+10+30 = 42 originally.


The Math expectation of the win value is


    {{{3*(2/42) + 2*(10/42) - 1*(30/42)}}} = {{{(3*2 + 2*10 -30)/42}}} = {{{-4/42}}} = {{{-2/21}}}  of a dollar.     <U>ANSWER</U>
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