Solution:

The cow that stands out is marked. Check the black spots.

Solution:

16-days

In 15-days, he will climb 15-inch and when he climbs 5 inch more, he will be out of the well :-)

Solution:

A
D
C
A
B

Solution:

There is a simple logic to solve this question.
The size of the chocolate is 2 x 8. Thus, you need to have 2 x 8 = 16 pieces.
Every time you break the chocolate, you will get one extra piece.
Thus, to get 16 pieces, you must break it (16 - 1) = 15 times.

Solution:

What is the correct time ?

Solution:

7

Explanation:
8th is bald man head, check the video below.

Solution:

Step 5 is invalid, because we are dividing by (x-y), and since x=y, we are thus dividing by 0. This is an invalid mathematical operation (division by 0), and so by not following basic mathematical rules

Solution:

Both will rotate at Same speed.

Explanation:
Gears of the same size will always rotate at constant speeds despite any smaller or larger gears in between them.

Solution:

Align the toothpicks to form TEN. Use one toothpick for each of the lines.

Solution:

The figure tells that B is located to the North-East of E.

Solution:

If you see the picture, they formed a pentagonal shape and achieved the required.