Find the missing letter in the last circle logically in the given below picture.

Using four sevens (7) and a one (1) create the number 100. Except for the five numerals, you can use the usual mathematical operations (+, -, x, :), root and brackets ()

What is so fragile that saying its name breaks it?

Here is a mathematical expression that also secretly tells a movie name. What movie is that?

Solve below rebus puzzle?

Sherlock Holmes was challenged to make a pre-drawn line smaller without erasing it. He did it in fractions of seconds. How?

I came first on earth but second on the heaven.
I also came twice in a week but found just once in a year.
I stay away from months but you can find me in February.

What am I?

Irene killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

What number do you get when you multiply all of the numbers on a telephone's number pad?

When it is alive we sing, when it is dead we clap our hands. What is it?