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.

mr. flanders’ class sold 47 doughnuts and   mr. rodriquez’s class sold 38 cartons of milk

step-by-step explanation:

let x be the number of doughnuts sold by mr. flanders’ class and y be the number of cartons sold by mr. rodriquez’s class.

1. together, the classes sold 85 items, then

x+y=85.

2. both classes earn earned $104.49 for their school. if doughnuts were sold for $1.35 each, then x doughnuts costed $1.35x. if cartons of milk were sold for $1.08 each, then y cartons costed $1.08y. hence,

1.35x+1.08y=104.49.

3. solve the system of two equations:

sup

step-by-step explanation: