Respuesta :

Answer:

oki! Mizuki here to help! 12 will be your answer!

Step-by-step explanation:

Soo... The ratio of blue to green is 4:3 right?

and there are 21 balloons!

4 + 3 is 7! So we divide 21 by 7 and get 3!

Then we multiply 3 by the number of blue balloons(aka 4) and get 12!