Answer :
Let:
x - green marbles
4x - red marbles
x/2 - blue marbles
[tex]x+4x+\frac{x}{2}=33|\cdot2\\ 2x+8x+x=66\\ 11x=66\\ \boxed{x=6}\\\\ \boxed{4x=24}\\\\ \boxed{\frac{x}{2}=3} [/tex]
x - green marbles
4x - red marbles
x/2 - blue marbles
[tex]x+4x+\frac{x}{2}=33|\cdot2\\ 2x+8x+x=66\\ 11x=66\\ \boxed{x=6}\\\\ \boxed{4x=24}\\\\ \boxed{\frac{x}{2}=3} [/tex]