You get a "sum" when you add numbers together.
Answer:
Blue balloons = 12
Step-by-step explanation:
Total no of balloons = 21
Let us assume that the ratio of blue balloons to green balloons is 4:3.
Let there are 4x blue balloons and 3x green balloons.
ATQ,
4x+3x = 21
7x = 21
x = 3
Blue balloons = 4x
= 4(3)
= 12
Hence, she will have 12 blue balloons at her party.