Replace the question mark with the correct number in below Picture:

A mathematician couple was having a Frappuccino in Starbucks sitting opposite to each other. Suddenly the guy noticed the text written on the paper in front of them and exclaimed that it was wrong. The girl denied it and said it is appropriate. Both are correct. What is written on the paper?

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 am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

By including only four matchsticks in below picture, you have to make "Four Triangles And Two Squares"

Can anyone tell me a word in the English dictionary which has a silent 'z'?

Why are televisions attracted to people?

Riddle me this, Riddle me that,
What am I? I am made of wood, but you can't see me down?

If you drop me I’m sure to crack, but give me a smile and I’ll always smile back. What am I?