x=trees ; y=shrubs
211.25 = 5x + 15y
211.25 = 5(y+15.25) + 15y
211.25 = 5y + 76.25 +15y
211.25 = 20y + 76.25
135=20y
y=6.75
Each shrub costs P6.75.
While each tree (represented by x) costs 6.75+15.25 or P22.00
Check:
5 trees and 15 shrubs
= 5(22) + 15(6.75)
= 110 + 101.25
= 211.25