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?

Answer 1

noble for=60

Douglas for =40

`5n + 3d = 420.....1\\ 12n + 9d. = 1080.....2 \\ \\ 5n = 420 - 3d \\ n = 420 - 3d / 5....3 \\ 12(420 - 3d) / 5 + 9d = 1080 \\ 5040 - 36d / 5 + 9d / 1 = 1080 \\ 5040 - 36d + 45d / 5 = 1080 \\ 5040 + 9d / 5 = 1080 \\ 5040 + 9d / 5 = 1080 \\ 9d + 5040 = 5400 \\ 9d = 360 \\ d = 40 \\ and n = 60 \\ 300 + 120 = 420 \\ 720 + 360 = 1080`