Helena uses a mixture of compost and topsoil in her garden. she purchased a total of 10 cubic yards of compost and topsoil for $180. if compost costs $25 per cubic yard and topsoil costs $15 per cubic yard, how many cubic yards of topsoil did she purchase?
a.)3
b.)4.5
c.)5.5
d.)7

7 cubic yard

Step-by-step explanation:

Let the compost purchased be x cubic yard

And the topsoil purchased be y cubic yard

Hence

x+y=10 (A)

Also

Cost incurred in buying compost at a rate of $25 per cubic yards = 25x

Cost incurred in buying topsoil at a rate of $15 per cubic yards = 15y

Total cost incurred = 25x+15y=180

Diving whole equation by 5 we get

5x+3y=36 (B)

Multiply A by 3 and subtract it from B

5x+3y=36

- - -

3x+3y=30

2x=6

x=3

Putting this value in A

x+y=10

3+y=10

y=10-3=7

Hence she purchased 7 cubic yards of topsoil.

its 8

step-by-step explanation:

a line is an defined derm because it

a)contains an infinite number of points b) can be used to create other geometric shapes c)describes something that does not have width or depth d) is a term that does not have a formal definition. a line is an undefined term because it: contains an infinite number of points.