Question

A student government organization is selling Christmas trees as a fundraiser. On Friday, they sold 5 noble fir trees and 3 douglas fir trees for a total of $420. On Saturday, 12 noble fir trees and 9 douglas fir trees were sold for a total of $1,080. What is the cost per tree for each type?
Nevermind, I figured it out. Noble fir trees= $60 and Douglas fir trees= $40

Answer 1

Lets x is price of noble fir trees and y - is price for douglas fir trees
students got 5x+3y=420$ on friday
and 12x+9y=1080
now we need just solve the system of equations
5x+3y=420 - multiply by 3
12x+9y=1080

15x+9y=1260
12x+9y=1080
substract second equation from first
15x-12x=1260-1080
3x=180 x=60$ - the price of noble fir trees

put value x=60 in first equation 5x+3y=420
5*60+3y=420
300+3y=420
3y=120 y=40$ - price of Douglas fir trees

Answer: Noble fir trees cost $60 and Douglas fir trees cost $40