I would suggest you to don't give up! There are lot of things you can learn from the book.
As I said the "correct" answer of the activities is not the important thing: what is important is to try to give an answer.
There are hundred of patches and solutions in the book, the activities are a mere 1-2% of the total, and they are there for the unique pourpose of making the reader reflect about what s/he has learned, what s/he can do with the program.
We worked 5 years on this project, and we believe that this is a route that can really improve your Max/MSP programming skill.
I think that not giving any answer doesn't help. Same for the reverse engineering exercises. You never know if you are right or wrong. And you may stay stuck for hours. Reminds me of some boring class exams... which is not what I expected.
Why stay stuck for hours? If you really can't find the answer, go on with the other chapters and return back later, you'll find the exercises easier!
Btw I forgot to reply to dthomas86, when he asked
But what does it mean by the successive keys correspond to something else rather than semitones? And how does this related to Table D in section 1.4 of the theory chapter?
The book suggested to "consult the ratios for natural frequencies in Table D of Section 1.4". So you have to compare the numbers generated by the kslider with the ratios of Table D. What are those ratios?
Are the ratios of the Activity A IDENTICAL to those of Table D or are they DIFFERENT? (hint: look at the number box connected to the kslider in the patch of fig. 1.66; does it seem to spit out the same ratios you find in Table D?).
How you would describe the patch ratios? (In your own words, without technicalities).
Still no idea? Don't worry, go on with the book and return back later.
With regard to reverse engineering, well this is part of the "core business" of the sound designer. A sound designer, imho, should learn (among other things) how to recreate (or approximate) a given sound.
Say you find a sound wich is perfect for a particular work you are doing. But you can't use it directly (because is badly recorded, or it is too short, too soft, or it is mixed with unwanted sounds etc.).
Well you can try to reverse engineer it, i.e. recreate it programmatically!
Again, what is important in the "reverse engineering" exercises is not to have the patch that created the sound. It is important to try to recreate the sound "with your hands". Maybe while you try to make a particular sound, you end up with a completely different sound, and maybe this sound is more interesting than the sound you were looking for! All this can improve your skill: just having the original patch does no good.
jut my two cents