What is common among 11, 69, and 88?

There’s a one-story house in which everything is yellow. Yellow walls, yellow doors, yellow furniture. What colour are the stairs?

Below, you will find the mathematical proof that 10 equals 9.99999?. But is that possible or there is something wrong about it? Can you find the error?

x = 9.999999...
10x = 99.999999...
10x - x = 90
9x = 90
x = 10

Make a sentence consisting of three words that have the whole alphabet.

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

On a special event at the prison, 5 prisoners John, Jacob, Krist, Tang, and Dang given a chance to go to a sauna and can bring one thing with them.

Following are the things that the prisoners bring with them.
John: A soda
Jacob: Thermos
Krist: Book named "How to kill"
Tang: A Walkman
Dang: Harmonica

Since it is a Sauna, no one can see each other. After a while When the steam is switched, Tang was found dead and there was blood all around.
J Bond was called and he instantly come to know who can be the murderer. How?

I’m light as a feather, yet the strongest person can’t hold me for five minutes. What am I?

What does below pictogram mean?

81 x 9 = 801. What must you do to make the this equation true?

By moving exactly three matchsticks can you make the below equation true.It can be solved by 3 ways.