2. The answer is 7. Add the two numbers together that are above each number on the bottom row, & the square root of their sum is the number on the bottom row.
3. The two words are BURRITO & TACO.
4. The gibberish written on the cover of the book held the answer to the puzzle. Once decoded, it reads: "THE PAGES OF THIS BOOK ARE POISONED." To find this, write the gibberish backward; then, separate the words just as they appear in the gibberish. That is, the first three letters are for the first word, the next five letters are for the second word, & so on. The beginning letters of each word in the code were also altered to throw the reader off. Smith was careful to handle the book with thick gloves, & to wrap it in plastic the first chance that he got. The book now appears in the Aremihc Archive. Have you seen it?
5. The soldiers marched across the bridge in step. That is, each soldier lifted his or her feet & dropped them at exactly the same time as all of the other soldiers. This placed a tremendous amount of pressure on the bridge, & caused the collapse. I understand that it is standard military procedure to order troops not to march across bridges in step, but the Commanding Officer of Bravo Company forgot this. Another plausible answer, found by a reader, is an EARTHQUAKE. There may be a few other possible answers, but only score them as correct if they don't violate the conditions set forth in the problem! Here is an answer sent in my a reader that I'm sure is better than mine:
The reason for the bridge's collapse is not the tremendous amount
of pressure, but the fact that they are marching with a certain rhythm.
Each bridge has a resonance rating, that is, a particular vibration that
makes the bridge resonate (you may have noticed that some like small
rooms or rooms with exposed pluming 'echo' when you sing (or your voice
hits) a certain note). If the soldiers happen to march at a multiple of
wavelength of the bridge's resonance, it will create a vibration
throughout the bridge. The will resonate, amplifying the vibration. If
this continues long enough, the bridge will actually vibrate itself off
it's foundation and collapse. This phenomenon was noticed a long time
ago, during military parades in cities that had bridges. A number of
bridges collapsed while the troops marched over them. I don't know when
the reason for this was discovered, but that is why it is an enforced
military practice to break the march and walk casually over a bridge.
So it is the shockwave produced by the simultaneous steps
(causing a uniform vibration) and not the pressure that can cause the
bridge to collapse. (Note that each bridge has a different resonance, and
it will only collapse if the march's beat is a multiple of the wavelength
of that bridge's resonance.)
6. Unscrambled, the letters can be placed together to make the name BELLEROPHON. Bellerophon slew the chimera in mythology.