Hard Riddles

If eight men can build eight walls in eight hours, how many men could build four walls in four hours?

What English word has three consecutive double letters?

What word looks the same upside down and backwards?

I am a three-digit number. My tens digit is six more than my ones digit. My hundreds digit is eight less than my tens digit. What number am I?

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 is in the photograph?

A cowboy rides into town on Friday, stays three days, and leaves on Friday. How is this possible?

If you have me, you want to share me. If you share me, you haven’t got me. What am I?

A blind man walked into a restaurant and ordered a meal. When he was done, he asked for the bill, looked at it, and left a tip. How did he read the bill?

Two fathers and two sons went fishing. They caught three fish which they divided equally, so each person got exactly one fish. How is this possible?

What is at the beginning of eternity, the end of time and space, the beginning of every end, and the end of every race?