Good Riddles

Question: What can be white and yellow at the same time?

Question: A spirited jig it dances bright, Banishing all but darkest night. Fire can't kill it but water can. Share it, it won't get less unless wind will ruin it.

Question: If you count 20 houses on your right going to the store and 20 houses on your left coming home, how many houses did you count?

Question: A school's computer system was recently hacked and the school has narrowed the pool of possible hackers to 5 people that were in the computer lab: Tyler, Justin, Chandler, Paige, and Shelley. Each of them gave three statements, two of which are true and one false.

Tyler
1. I didn't do it!
2. I've never hacked in my life.
3. Paige did it.
Justin
1. I didn't do it!
2. The attack was done from within the network.
3. I don't like Shelley.
Chandler
1. I didn't do it!
2. I've never seen Shelley in my life.
3. Paige did it.
Paige
1. I didn't do it!
2. Shelley did it.
3. Tyler was lying when he said I did it.
Shelley
1. I didn't do it!
2. Justin did it.
3. Chandler and I used to be friends.

Who hacked the system?

Question: What are the next two letters in the following series and why? WATNTLITFS__