gmatman1031 wrote:
How do you know that the formula needs to be volume? I understand how that would make sense in real life, but I don't see anything in the question that would indicate that.
The definition of proportionality (found
here and
here) dictates this. Also, since this question deals with joint proportionality, I found
this helpful as well.
grant1377 wrote:
My question is, can you assume that it's directly proportional from the question stem? Looking at a few of the answers above, it seems that some people have. If this was a P.S. problem instead of a D.S., the answer would depend on this assumption.
Yes. According to
this Wikipedia article: "If the term proportional is connected to two variables without further qualification, generally direct proportionality can be assumed."