Answer:
c) He should add between 1 cup and 2 cups of dirt.
Explanation:
ration of dirt to peat moss:
⇒ 8 parts dirt : 3 parts peat moss
⇒ x cups dirt : 1 cup peat moss
to find the value of dirt, take the ratio and turn it into a fraction
⇒ 8 : 3 =

⇒ x : 1 =

⇒
=

now, we multiply 1 on both sides to isolate x
⇒
x 1 =
x 1
⇒ 2.67 = x
⇒ 2 cups of dirt