The number that will come place in place of question mark is 0.

If you add the numbers in each diagonals, you will find that the sum is 25 every time.

4

The number in the upper row indicates the number of letters in the alphabetical form of the number below.

9 = Nine = four letters
Therefore the missing number is 4.

In this series, every single digits in in the middle of two prime number.

4 is in the middle of 3 and 5 which are prime.
6 is in the middle of 5 and 7 which are prime.

Thus, the numbers are 108 will be 138, 150 and 180.

The number will be 30.

1. (5 + 4) * 2 = 18
2. (12 + 8) * 3 = 60
3. (3 + 9) * 4 = 48
4. (4 + 2) * 5 = 30

132.

The solution lies in the fact that the series is list of sequential (prime numbers + 1) (101 103 107 109 113 127 131 being the prime numbers)

12l  8l  5l
12  0   0
4    8   0
0    8   4
8    0   4
8    4   0
3    4   5
3    8   1
11  0   1
11  1   0
6    1   5
6    6   0

18

More hours => more burgers.
More boys => more burgers.

The time become twice (3 hours / 1.5 hours).
Boys become six times (9 / 1.5).

Number of burgers = 2 * 6 * Original(1.5)
= 18

I cannot identify the tablets by any means. Thus the only solution available is to cut each tablet in half and have them. In this way, it does not matter which tablet is for what purpose. I will be ultimately be having 1 of each.

The question that he asked was “What is the time?”

The culprit chose to die of an old age.