Solution:

As marked in the solution picture, all men in the background have the same face.

Solution:

52

Explanation:
The Last number in the column is represented by
(1st-number)(2nd-number) - (3rd-number)

Based on above formulla,
1st column logic 26 - 4 = 22
2nd colum logic 37 - 5 = 32
3rd colum logic 48 - 6 = 42;

Required numer i.e 4th colum logic is
59 - 7 = 52

Solution:

Pick 1st.

Explanation:
> Take 1 coin
> Pick the opposite number of coins from the other soldier i.e if other soldier pick 1 coin, you pick 2 and if he picks 2 coins you pick one
> After 15 moves, coins remaining will be 23 - 1 - 7(2+1) = 1
> The other solider need to pick the last and he will loose.

Solution:

2nd Feb

Explanation:
a.b X a/b = 1
2.5 x 2/5
= 5/5
= 1

Solution:

Eyes

Explanation:
We have black but we are not tea seeds - Pupil of eye
We have white buts we are not lime - sclera of eye
We have water but we are not a river - general tears in eyes to protect eyes.
We have feather but we are not birds - lashes.

Solution:

One of 57620 or 57628 must be the secret code.

Explanation:
Hint-1: 79314
Only 7 is there and in wrong

Hint-2: 95643
6 is in the right position while 5 is not

Hint-3: 57319
5 and 7 are in the right position

Sum Hint: A + B + C + D + E = D*10 + E
CaseA - 57620
5 + 7 + 6 + 2 + 0 = 2 * 10 + 0
20 = 20

CaseB - 57628
5 + 7 + 6 + 2 + 8 = 2 * 10 + 8
28 = 28

Solution:

7 Trips

Explanation:
Send 2+5+9 = 16
Bring back 9
Send 3+4+9 = 16
Bring back 9
Send 1+7+8 = 16
Bring back 1
Send 1+6+9 = 16

Solution:

CANNOT BE CRACKED

Explanation:
This code can be cracked with the help of table below.
i.e
31 => 3rd row and 1st column => C
11 => 1st row and 1st column => A
33 => 3rd row and 3rd column => N
and so on....

Solution:

Murder.

Explanation:
1. There are signs of the struggle in the room as the clock is broken.

2. Two water glasses in the room indicate the presence of two people which also suggest that the killer is known to the victim.

3. There are a book and a pen on the bed which indicates that the dead person was reading and a suicide note was written from another pen which seems to be planted.

4. The man crutches are too far from the man.

Solution:

Either Rain Cloud Or Air

Explanation
=== Rain Cloud ===
I don't have a mouth but can roar - Thunder
I don't have eyes but can cry - Rain
I am really good - Rain is good
but bad sometimes - Storms
Without me, all will die - rain is the necessity for agriculture and human being

=== Air ===
I don't have a mouth but can roar - Wind
I don't have eyes but can cry - Moisture
I am really good - Rain is good
but bad sometimes - Hurricanes
Without me, all will die - Oxygen