Solution:

The thief is the Pakistani guy. It is because the flag of Japan looks same when upside down and no one can tell if it is upside down. So, he was telling a lie.

Solution:

30

Explanation:
It's very difficult to count an actual number of balls but it can be counted mathematically as illustrated below.

Balls in lowest level most level, say level 1 : 4 * 4 = 16
Level2 => 3 * 3 = 9
Level3 => 2 * 2 = 4
Leve4 => 1

Summing up 16+9+4+1 = 30.

Solution:

3012

Explanation:
A)
Five Commando alloted 5 room each, Number of rooms = 5 * 5 = 25

Number of huge Tiger = 25 * 5 = 125
Number of small Tigers = 125 * 5 = 625
Total tigers = 625 + 125 = 750

Number of legs of tigers = 750 * 4 = 3000 ..............................(1)

B)
There are 5 soldiers =>
Number of legs of soldiers = 5*2 = 10 .......................(2)

C)
Your leg = 2 ............(3)

Summing all , 3000 + 10 + 2 = 3012

Solution:

301

= Explanation =
Time1 : When there are two pirates, 301/2 => remainder 1
Time2 : When there are three pirates, 301/3 => remainder 1
Time3 : When there are three pirates, 301/4 => remainder 1
Time4 : When there are three pirates, 301/5 => remainder 1
Time5 : When there are three pirates, 301/6 => remainder 1
Time6 : When there are three pirates, 301/7 => remainder 0

Solution:

To add commutative balance in the puzzle above is mistake
You will get this when I show you another way to spend $50.

Spent Balance
5                   45
5                   40
5                   35
5                   30
5                   25
5                   20
5                   15
5                   10
5                   05
5                   00
=========
50                   225

The numbers i choose smartly to confuse readers.

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:

111111111

Explanation:
It's a maths magical square root series as :
Square root of number 121 is 11
Square root of number 12321 is 111
Square root of number 1234321 is 1111
Square root of number 123454321 is 11111
Square root of number 12345654321 is 111111
Square root of number 1234567654321 is 1111111
Square root of number 123456787654321 is 11111111
Square root of number 12345678987654321 is 111111111 (answer)

Solution:

Both 3 and 4th

Explanation:
- The water in tank1 will get filled up to the connectivity of tank1 and the tank2 and then it will start flowing to tank2.
- The water in tank2 will get filled up to the connectivity of tank2 and the -tank3 and then it will start flowing to tank3.
- The water in tank3 will get filled up to the connectivity of tank2 and the tank3 and then it will start flowing to tank3.
- As the outlet of tank3 and inlet of tank4 are not at the same level, water will continue to fill tank3 till the inlet of tank4.
- Now both the tank3 and tank4 fill simultaneously until both fill together.

Solution:

8! minutes

Explanation:
28 days x 24 hours x 60 minutes = 40,320 = 8! minutes.

Solution:

It can be done as shown in the picture below.