Word Problem HELP!!!! Need to know how to set up the equation.?

Question

There are 850 Douglas fir and ponderosa pine trees in a section of forest bought by Sawz Logging Company. The company paid an average of $300 for each Douglas fir and $225 fir each ponderosa pine. If the company paid $217,500 for the trees, how many of each kind did the company buy?

Answer 1

let D=number of Douglas fir trees
let P= number of Ponderosa pine trees
D=850-P
P=850-D
850-P*300+850-D*225=217500

try it.
it might work

Answer 2

x = number of Douglas firs
y = number of ponderosa pines
x + y = 850

300x + 300y = 255000
300x + 225y = 217500
75y = 37500
y = 500 ponderosa pines
x = 350 Douglas firs

Check
350*300 + 500*225 = 217500
105000 + 112500 = 217500

Answer 3

217,500=300x+225y
x+y=850
x=Douglas Pondrosa=Y