Question

Mrs. Grijalva hired a landscaping company to landscape her back yard. The company has a standing policy to plant 3 bushes for every tree planted. The company charges $75 for each tree planted and $20 for each bush. Mrs. Grijalva was billed for $810 after the planting was complete. How many bushes did the company plant in Mrs. Grijalva’s back yard?
A.
2
B.
6
C.
18
D.
54

Answer 1

so she got billed 810
they planted "t amount" of trees
they also planted "b amount" of bushes

so her invoice was => (t * $75) + (b * $20) = $810

Answer 2

what equation would that give us?

Answer 3

75+20=810?

Answer 4

well, you're missing the variables
but close
75t + 20b = 810

now, we know that the landscaping company policy is to plant 3 bushes for every tree
so that makes the amount "b"
1 tree
1 bush + 1 bush + 1 bush
1 tree
1 bush + 1 bush + 1 bush
1 tree
1 bush + 1 bush + 1 bush

so amount wise, if you say plant 3 trees, you'd plant 3(3) bushes
that makes the bushes
b = 3t
so our equation will be
\(\bf 75t + 20(3t) = 810\)
then just solve for "t" and that'd give you how many trees, multiply that by 3, and that's how many bushes they planted