What does the below image rebus riddle means ?

The person who makes it has no need for it; the person who buys it has no use for it. The person who uses it can neither see nor feel it. What is it?

How many people must be gathered together in a room, before you can be certain that there is a greater than 50/50 chance that at least two of them have the same birthday?

A maths symbol is hidden in the below Bar Graph. Can you decipher it?

What word begins and ends with an E, but has only one letter?

What can go up a chimney down, but can’t go down a chimney up?

What English word has three consecutive double letters?

Teacher ask the student

'Why are you standing on that chair in music class ?'.

what did student replied ?

Steffi's daughter Jazelle needs to be picked up from school every day.
Steffi asks one of her colleagues to pick up Jazelle from the school. Steffi devised a password system to confirm that Jazelle goes with the correct colleague only.

The password on Monday was SJM16.
The password on Wednesday was TAW39.

What will the password be for Friday?

In The 1st month of this year(the year 2013), I noticed that the date 13-1-13 (13 January 2013) is special.

This date is special as:

Date * Month = Year.

Can you figure out which year of this century has a maximum number of such dates?