1) 20 minutes
First, put in one toadfish. Five minutes later, when the time comes to flip it, put in the second toadfish. After 10 minutes, the first fish is done and you flip the second fish, adding in the third fish. After 15 minutes, you flip the third toadfish and take out the second. After 20 you're done.
2)8136
3) Three.
After the first skeleton, you could have either red or blue. After the second, you could have red and blue. The third, however, has to be either red or blue, matching one of the first two.
4) A decimal point. 5.9
5)10
6) 13:29. If the amount doubles every minute, then it took a minute for it to go from half full to full.
7) 120 graboids, 64 shriekers, 12 firefly queens
8 ) I'm going to be a smartass and say 24 km. No matter how long the Phoenix walks, it's always the same 24 km.
All of these were easy, except for the last one, which you googled anyway. I'll hit back with harder stuff when I think of one.