Answer:
Step-by-step explanation:
You have the equations set up correctly. I will use r and b as the variables to make it easier to follow.
12r + 8b = 70
20r + 12b = 110
First let's solve one of the equations for one of the variables.
12r = 70 - 8b

Now plug that in for r in the second equation.

Simplify



b = 5 grams
Now plug 5 in for b in one of the original equations to find r.
12r + 8(5) = 70
12r = 30
r = 2.5 grams
So the red marbles weigh 2.5 grams, and the blue marbles weigh 5 grams.
Answer:
0+0.1+0.01/ zero and eleventh hundredths
<em>I hope this helped if I got it wrong i'm sorry it has been a while since I have done this XD</em>