The recyclables have been sorted into plastic and glass. the number of plastic items is 30 less than nine times the number of glass items. the recyclables are 85% plastic. how many glass items are there?
a. 6
b. 9
c. 15
d. 18

B

Step-by-step explanation:

We will use substitution method after writing 2 equations to solve for number of glass items.

Let number of glass items be g and number of plastic items be p

"The number of plastic items is 30 less than nine times the number of glass items":

We can write the equation as  

"The recyclables are 85% plastic":

This means that plastic (p) is 0.85 of  the total (p+g). Thus we can write equation as  

We can substitute the expression for p in first equation into 2nd and solve for g:

The number of glass items is 9

.

step-by-step explanation:

.

answer: c

(2, -4)

goes 7 to the

(9, 4)

easy