Question 96390
D+P=850 OR D=850-P
300D+225P=217,500 NOW SUBSTITUTE (850-P) FOR D IN THIS EQUATION & SOLVE FOR P:
300(850-P)+225P=217,500
255,000-300P+225P=217,500
-75P=217,500-255,000
-75P=-37,500
P=-37,500/-75
P=500 NUMBER OF PONDEROSA PINE TREES
850-500=350 NUMBER OF DOUGLAS FIRS.
PROOF
300*350+225*500=217,500
105,000+112,500=217,500
217,500=217,500