Man... that's a TOUGH ONE! I hardly know any of these... not that it takes a tough one to cause that to happen....
1) Atlantic
2) I think this one is a trick question and can't mathematically be done (by me, anyway); how can you add half your own weight to your weight, and still end up with your original weight? A 1lb fish, for example, according to the instructions in the riddle, would now weigh 1.5 lbs [adding (1.0 lb) + (1/2 his weight of 1.0 lb) = 1.5 lbs]... am I making this more complicated than the question warranted--I do that sometimes....
3) 100 (if a "standard" record is a 33-1/3 rpm)
4) I can get to 101... then they can ask for a 1 lb box (since they have all those boxes) and return the last 1 lb... no? okay....
5) Wyoming
6) nothing comes to mind... hmmmm...
7) no, it just looks like she does
8) tuba, trumpet, trombone... uh... ummm... tambourine? triangle? tympany drum?
9) "slinky"... ha, get it?? (okay, no idea)
10) R, R, R, R