What is the next number in this matchsticks series riddle?

I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

You are given four tennis balls and asked to arrange those balls in a manner that the distance between each one of them is exactly equal. How will you do it?

Two brothers were watching a horror film on video late one night. One brother dozed off and dreamed that he was being chased by the crazy man from the movie, who was trying to kill him. In the dream, he hid in a cupboard. There was no sound except his heart pounding, and he had no idea where his crazed captor was. He was terrified! At that moment, the video finished, and his brother put his hand on the shoulder of his sleeping sibling to wake him. The shock at that tense moment was enough that the sleeping brother suffered a massive heart attack and died instantly. True or false?

Can you make four (4) nines (9) equal 100?

How can you leave a room with two legs and return with six legs?

They are three errirs in this question. Can you find them?

A man is looking at a photograph of someone. His friend asks who it is. The man replies, “Brothers and sisters, I have none. But that man’s father is my father’s son.” Who was in the photograph?

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

Count the number of triangles in the picture below: