Solution:

3

The total sum is always 17.

Solution:

When you are using roman numerals.

Solution:

Letter 'O'

Solution:

The watch on the left is a toy. The minute arm is too long, so it can't pass around the face when it moves.

Solution:

9

4x + 21 = 57
4x = 36
x = 9

Solution:

A Bank

Solution:

The clock has the letter B instead of the number 8.

Solution:

Fire

Solution:

11

10 people have pair of eyes, so 20 eyes.
So we have 10 people in addition to the man who dropped the book. She cannot look at herself, but she is still in the Church.

Solution:

The girl in the red shirt.
As she is eating a sandwich that looks like it's years old, and that might kill her.