Yes, thank you. I just realised. But now I found the answer. It's =13.19
I'd like to see your work, in detail, as well as how you interpreted the problem. I mentioned several errors in it in #4.
It appears that you corrected it to something like this:
Air is being pumped into two spherical balloons that stand side-by-side (with their centers horizontally aligned) and are initially 1 metre apart (between their centers).
The volume of the first balloon at any given time, ?1 cm3, is increasing at a rate of 0.5?1 cm3/s. Initially, ?1=5??^3.
The volume of the second balloon at any given time, ?2 cm3, is increasing at a rate equal to 0.6? cm3/s. After 2 seconds, ?2=8??^3.
Determine how long it will take for the balloons radii to be 20 cm apart (between their surfaces). Justify your answer.
The main trouble I have with this interpretation is the discrepancy in how you are measuring distance between balloons, implied by your work
This appears to say that 100 is the (
fixed) distance between their
centers, while 20 is the final distance between their
surfaces.
To me, if two balloons "stand side by side", I would see them more like this:
But that would make the problem a lot harder, so I don't mind that change to
Have you asked about the meaning of the problem? Is what you showed us an exact copy, or did you paraphrase it? Can you show us an image of the original?