Every words stands for unique digit that makes the arithmetic equation true

SEVEN + SEVEN + SIX = TWENTY.

What are the digits ?

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

Railroad Crossing, look out for the cars. Can you spell that, without any R's ?

What is the next number in the series?

15 29 56 108 208 ?

Can you find the 09 errors in the picture below?

Keyboard words are not in alphabetical order, Why?

You are given 16 witch hats. The hats are divided in four different colours – red, blue, green and yellow. Every colour has been assigned to four hats. Now each of the hat will be glued with a label of an arithmetic sign – ‘+’, ‘-‘, ‘x’ or ‘/’. But you can label one sign only once on one colour. In such an arrangement, the hats can be uniquely defined by its colour and symbol.

Can you arrange all the 16 hats in a 4x4 grid in a fashion that no two rows and columns have a repetition of colour or sign?
We have arranged four hats in the below picture to assist you.

I have branches, but no fruit, trunk or leaves. What am I?

There is something which you can be arrested for attempting but not for successfully completing.

This is a picture puzzle. You have to guess the name of the movie that can be related to the picture.