What is common among 11, 69, and 88?

One absent-minded ancient philosopher forgot to wind up his only clock in the house. He had no radio, TV, telephone, internet, or any other means for telling time. So he travelled on foot to his friend's place a few miles down the straight desert road. He stayed at his friend's house for the night and when he came back home, he knew how to set his clock. How did he know?

Decode below rebus
D
N
A
T
S , D

You need to pick one entry from pot A and one from pot B to have a perfect match. Can you do it?

What is the centre of gravity?

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

Can you make a fire with just a single stick?

What does this rebus means ?

PROG WORKRESS

Can you find the odd one out from the below words ?

First Second Third Forth Fifth Sixth Seventh, Eighth Nine Ten Eleven Twelve.

How many words can a pen with half refill write?