In a box, there are black pens, red pens and green pens the ratio of black pens to not black pens is 9:11
the ratio of green pens to not green pens is 3:5
fins the ratio of black pens to red pens to green pens

What do we know?

There are 9 black pens and 3 green pens.

What else do we know?

We know that 11 of the pens aren't black, and 5 of them aren't green.

Black pens (9) : red pens (6) : green pens (3)

How'd I get 6?

If 11 pens aren't black, they had to be green, but 5 of them weren't green. So, I subtracted 11 from 5 to get 6 red pens.

I hope that makes sense.

Final

9:6:3

WARNING: I could be wrong as I'm not fully sure, but this is what I think.

if y=4x then you will substitute 4x in for y in the second equation.

8x + 4x = 18 combine like terms

12x = 18 divide by 12 on both sides

x = 18/12 or 3/2

now replace x in the first equation with 3/2 to get

y = 4 3/2

y = 6

the answer is a

(3/2,6)

hope that .

brainliest is always apprectiated