Question

Jillian is trying to determine what helium tank pressure she needs to fill balloons for the student council dance. Find the unknown numbers in the table until you find the best answer to the question.

Which cylinder pressure will Jillian need if she plans to fill 90 balloons?

Tank Pressure and Balloon Quantity
Pressure in the helium cylinder (psi)
Number of 9-inch balloons
100
30
150
?
200
?
250
?
300
?
150
200
250
300

Answer 1

The answer depends on the volume of each balloon and the volume of the helium cylinder. Assuming that each 9-inch balloon has a volume of about 0.25 cubic feet and the helium cylinder has a volume of about 15 cubic feet, we can estimate the number of balloons that can be filled at different pressures:

- At 100 psi, the cylinder can fill about 600 balloons
- At 200 psi, the cylinder can fill about 1200 balloons
- At 300 psi, the cylinder can fill about 1800 balloons

Since Jillian plans to fill 90 balloons, she only needs a fraction of a cylinder. At 100 psi, each balloon would be filled with about 0.04 cubic feet of helium. To fill 90 balloons, Jillian would need about 3.6 cubic feet of helium, which is about 24% of the cylinder. Therefore, Jillian would need a tank pressure of about 100 psi to fill 90 balloons.