Why Aeroplane windows are round?

Get total of 120 by using five zeros 0,0,0,0,0 and any one mathematical operator.
Do you ?

It is a six-letter word.
The first four letters are me.
The second and last letters are the same.
The fourth second and last letter is payment.

Who is it?

2, 3, 5, 9, 17, _ What is the next number in the sequence?

Which word is least like the others? Third, fourth, fifth, sixth, seventh, eighth, ninth?

The first box has two white balls. The second box has two black balls. The third box has a white and a black ball.

Boxes are labeled but all labels are wrong!

You are allowed to open one box, pick one ball at random, see its colour and put it back into the box, without seeing the colour of the other ball.

How many such operations are necessary to correctly label the boxes?

I am the largest in my family of fifty.
The youngest of our family lives separately from the rest of the family and so do I.
I am regarded as harsh and tough.
I am so large, you cut me in two equal halves,
each half would still be larger than the second largest member of the family.
Who am I?

There are forty elephants and they have forty-fore heads. How can this be possible?

What does the following represent?

N N N N N N N

A A A A A A A

C C C C C C C

What does this Rebus Picture mean?