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

There's one "sport" in which neither the spectators nor the participants know the score or the leader until the contest ends.

What is it?

What is the next number in the series?

15 29 56 108 208 ?

As shown in the image, the nine Dogs are square fenced. By constructing just two square fences can you make sure that two Dogs cannot meet each other without crossing the fence?

How can a man go eight days without sleep?

I am a five-letter word under you,
Remove the first letter and I am above you,
Remove the second as well and I am around you.

Who am I?

What brings you down but never up?

using four eights (8) and a one (1) and one mathematical symbol , create the number 100

Double it and multiply it by 4. Then divide it by 8 and you’ll have it once more. What number is it?

Two boys were admitted to a school. When the headmaster asks them about their parents, they tell him that they have same parents (father and mother). On further inquiry, it turns out that they both share the same date for their birthday.

"Are you twins," ask the headmaster.
"No," replies the boys.

Is it possible?