I know:

- Formula for a sphere's volume:
- Diameter of balloon is 20cm = radius of balloon is 10cm.
- Difference of 5cm in the radius is:
- 1333.3 - 166.67 = 1166.63
- This is not a choice, so I am obviously wrong.
- Why I think I am wrong: is not in the form of a rate. It needs to be in the form of .
- I can't think of how to do this.
- Lastly, my practice test states that this question will see if I
I clearly did not use Calculus, and quite honestly, I'm don't know how.understand the historical development and application of calculus.