Solution:

Nice Personality.

Explanation:
N + ice + Purse on "ality" =>Nice Personality

Solution:

2100 miles.

Each vowel equivalent to 500 and each consonant equivalent to -200

Solution:

The Password.

Explanation:
Clues 2 and 5 are correct and rest are lies.

Solution:

Sam : 2
Dean : 5
Castiel : 7

Age diff
7 - 2 = '5' is prime
7 - 5 = '2' is prime
5 - 2 = '3' is prime

Solution:

"World War I" was named after after "World War II"

Solution:

It can be done in 8 moves as shown in the animated image below.

Solution:

199 - 99

Solution:

12 steps:

Steps 11 Liter jug 6 Liter Jug
1. 11 -
2. 5 6
3. 5 0
4. 0 5
5. 11 5
6. 10 6
7. 10 0
8. 4 6
9. 4 0
10. 0 4
11. 11 4
12. 9 6 ==> i found 9 liter in 11liter jug(as required)

Solution:

Isaac Newton picks up a piece of wood and lights it from the fire on the west end of the island.

He then quickly carries it near the east end of he island and starts a new fire. The wind will cause that fire to burn out the eastern end and he can then shelter in the burnt area.

(Funny Part : Isaac Newton survives the fire, but dies of starvation, with all the food in the forest burnt )

Solution:

Birbal drew another line that was larger than the pre-drawn line. Now the pre drawn line was smaller.

Solution:

If you see the picture, they formed a pentagonal shape and achieved the required.