Answer:
Step-by-step explanation:
We set up the problem like this: 39 = x + (x + 7)
x = blue marbles
39 = 2x + 7
Subtract 7 from each side
32 = 2x
Divide each side by 2
16 = x
39 = 16 + (16 + 7)
Blue marbles = 16
Green marbles = 16 + 7 = 23
There are 23 green marbles and 16 blue marbles.
