Solution:

The only possible way to do it is to form an equilateral triangle pyramid and then place the balls at the corners of the figure. Yes, you will have to use 3 dimensional figure.

Solution:

24

Explanation:
There are a total of 24 triangles in the given figure.

To make it easy to understand, we have put numbers on each distinct triangle. So let us start counting them now.
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, (1+2), (1+2), (1+2+3), (1+2+3+4), (2+3), (2+3+4), (3+4), (5+6), (5+6+7+8), (7+8), (1+2+5+6), (3+4+7+8), (2+6+9), (3+7+10), (6+9), (7+10) and (6+7+9+10).

Solution:

The image that we have attached here is self-explanatory. You just have to move four matches and you can obtain this figure.

Solution:

The missing tile will be 3.

Explanation:
0 + 0 = 0
1 + 2 = 3
0 + 2 + 2
1 + 4 = 5
3 + 1 = 4
6 + 1 = 7
3 + 3 = 6
6 + 3 = 9

If you see the patter, with each pair the total sum is increasing by three and then decreasing by 1. Therefore the missing tile will be 3.

Solution:

76

Solution:

Picture D.

Explanation:
Since the number of black dots are increasing in picture D, so it can be only solution.

Solution:

Feeling on top of the World

Solution:

If you see the picture, you can find out seven squares - five 1x1, one 2x2 and one 3x3. See the dotted lines and the black matchsticks to know how we have moved the matchsticks.

Solution:

17

Explanation:
You can see the center circle right?
There are 16 more circles. Probably you missed them. Just concentrate on the center circle for a moment and you will find the other 16 circles.

Thus there are a total of 17 circles in the given picture.

Solution:

Logic Matchsticks Problem can be solved as shown in image below