Question 43212
Amount of Douglas firs = d
Amount of Pine trees = p
Equations:
{{{d + p = 850}}}
{{{300d + 225p = 217500}}}
Combine:
{{{-300d - 300p = -255000}}}
+
{{{300d + 225p = 217500}}}
=
{{{-75p = -37500}}}
{{{p = 500}}}
PLUG:
{{{d + p = 850}}}
{{{d + 500 = 850}}}
{{{d = 350}}}