Count the number of triangles in the below picture?

Can you find the missing letter in the sequence?
S - T - I - L - ? - T - F - Y - C

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?

John and Jenni are a married couple. They have two kids, one of them is a girl. Assume safely that the probability of each gender is 1/2.
What is the probability that the other kid is also a girl?

Hint: It is not 1/2 as you would first think.

If you're 8 feet away from a door and with each move you advance half the distance to the door. How many moves will it take to reach the door?

Rearrange the letters in "new door" to make one word.

If a zookeeper had 100 pairs of animals in her zoo, and two pairs of babies are born for each one of the original animals, then (sadly) 23 animals don’t survive, how many animals do you have left in total?

What does Alexander the Great and Winnie the Pooh have in common?

100 prisoners are stuck in the prison in solitary cells. The warden of the prison got bored one day and offered them a challenge. He will put one prisoner per day, selected at random (a prisoner can be selected more than once), into a special room with a light bulb and a switch which controls the bulb. No other prisoners can see or control the light bulb. The prisoner in the special room can either turn on the bulb, turn off the bulb or do nothing. On any day, the prisoners can stop this process and say "Every prisoner has been in the special room at least once". If that happens to be true, all the prisoners will be set free. If it is false, then all the prisoners will be executed. The prisoners are given some time to discuss and figure out a solution. How do they ensure they all go free?

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