Answer:
$15
Step-by-step explanation:
Let bushes = b and trees = t.
We can write:
12b + 15t = 600 (Equation 1)
8b + 20t = 680 (Equation 2)
24b + 30t = 1200 (Equation 3 -- Multiply Equation 1 by 2)
24b + 60t = 2040 (Equation 4 -- Multiply Equation 2 by 3)
30t = 840 (Subtract Equation 3 from 4)
t = 28 (Divide by 30)
12b + 15 * 28 = 600 (Substitute t = 28 into Equation 1)
12b = 180 (Simplify)
b = 15 (Divide by 12)
