A landscaping company has two orders for bushes and trees.
Order 1 for 12 bushes and 15 trees that will cost the customer $600
Order 2 for 8 bushes and 20 trees that will cost the customer $680
What is the cost of one bush?

Question

A landscaping company has two orders for bushes and trees.
Order 1 for 12 bushes and 15 trees that will cost the customer $600
Order 2 for 8 bushes and 20 trees that will cost the customer $680
What is the cost of one bush?

nurali · Answer

Let the cost of 1 bush be x and the cost of 1 tree be y.

"12 bushes and 15 trees that will cost the customer $600"
12x + 15y = 600   ----- (1)

"8 bushes and 20 trees that will cost the customer $680"
8x + 20y = 680  ------ (2)

Eliminate y from (1) and (2) and solve for x.
12x + 15y = 600 ----- (1)
This can be simplified by dividing by 3:
4x + 5y = 200

8x + 20y = 680 ------ (2)
This can be simplified by dividing by 4:
2x + 5y = 170

So we have:
4x + 5y = 200
2x + 5y = 170
To eliminate y, subtract the two equations. 
If you subtract the two equations, the 5y will cancel and you get
2x = 30
x = 15

So the price of one bush = $15.