What is common among 11, 69, and 88?

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

Decode below rebus
D
N
A
T
S , D

Why Wine Glass Stem is so long?

Why are televisions attracted to people?

In a university, a professor gave a set of three problems to the three brilliant students of his class. See the image for the questions.

What brings you down but never up?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

I have two coins.
* One of the coins is a faulty coin having a tail on both sides of it.
* The other coin is a perfect coin (heads on side and tail on other).

I blindfold myself and pick a coin and put the coin on the table. The face of the coin towards the sky is the tail.

What is the probability that another side is also tail?

What comes
Once in a Year
Twice in a Month
4 times in a Week
6 times in a Day