Question 310870
Don't solve for them, solve for P/N.
(x1+x2+x3+...+xp)/P={{{70}}}
(y1+y2+y3+...+yn)/N={{{92}}}
(x1+x2+...+xn+y1+y2+...yp)/(P+N)={{{86}}}
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(x1+x2+x3+...+xp)={{{70P}}}
(y1+y2+y3+...+yn)={{{92N}}}
(x1+x2+...+xn+y1+y2+...yp)={{{86(P+N)}}}
{{{ 70P+92N=86P+86N }}}
{{{ -16P=-6N}}}

{{{ P/N=6/16=3/8}}}