Answer:
11
Step-by-step explanation:
According to Boyle's law:

Thus,

Where, n is the number of the balloons
From the question, it is given that:
For balloon:
P =
Pa
V = 0.040 m³
For cylinder:
P =
Pa
V = 0.0031 m³
So,

n = 11.625
So, Maximum number of balloons = 11