What is the approximate diameter of the latex balloon after inflation?

[Dannbr]

Homework Statement

In a recent high altitude experiment, some physics students used 1500 liter of helium to inflate a latex sounding balloon that would ascend to an altitude of over 30 km. what was the approximate diameter of the (assumed spherical) balloon after inflation?

Homework Equations

volume of a sphere= (4/3)(pi)(r^3)

1 liter = 1.0E-3

The Attempt at a Solution

V=(4/3)(pi)(r^3)

so,

r = [(3V)/(4(pi))]^(1/3)

(1500liter)(1.0E-3m^3/1liter)= 1.5m^3

[((3)(1.5m^3))/((4)(pi))]^(1/3) = .710m

2r = 1.42m

Correct answer should be 3.1 m

Could someone help me out..

Thanks

 

[gneill]

The supposed correct answer seems out of line for the question posed. Are you sure the problem didn't involve the size of the balloon at 30km altitude? Or that the helium was in some initially compressed condition?

 

[Dannbr]

No, copied question word for word. Thanks for taking a look at it.