Solution:

569

Explanation:
Number in the triangle in ant-clockwise are: 15 12 and 18
The Central number is formed by there largest factor i.e
15=> 3 * 5 => largest factor is 5
12=> 2 * 6 => largest factor is 6
18=> 2 * 9 => largest factor is 9.

Therefore required number is 569.

Solution:

It can be done as shown below.

Solution:

24

Explanation:
21 * 4 - (4 * 4) = 68
12 * 4 - (4 * 4) = 32
17 * 4 - (4 * 4) = 52
10 * 4 - (4 * 4) = 24

Solution:

As shown in solution picture, flip the first number and stack on the second number, you will get fish eight and triangle respectively.

Solution:

This type of puzzle is referred to as an informal fallacy puzzle. The general idea is that the logic that is presented to the user appears at first glance to be correct, but in actuality has an error in it.
Actually,
Total pound spend by elder brothers = 9+9 = 18
=>17spend on shoes + 1pound (Kylian kept for himself)

Solution:

10.

Explanation:
Most of the people will give the answer as 6 or 3.
But the total number of holes are ten.
> 1 hole for the neck.
> 2 holes for the arms.
> 1 hole for the torso.
> 3 torn holes in the front.
> 3 torn holes in the back.

Solution:

-> Pour the water in the barrel.
-> Freeze it.
-> Pour the milk in the barrel.

Solution:

12

Solution:

The death was ruled a suicide.

Solution:

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