<PRE><B>Question 135071</B>
Probability that they play: {{{P[p]}}}
Probability that they do not play: {{{P[n]}}}


{{{P[p]=9P[n]}}} and {{{P[p]+P[n]=1}}}, so by substitution:


{{{9P[n]+P[n]=1}}}


Can you take it from here or do you need more help?


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