Riddle: There are five people. One of them shot and killed one of the other five. Which man is the murderer? 1. Dan ran in the NY City marathon yesterday with one of the innocent men. 2. Mike considered being a farmer before he moved to the city. 3. Jeff is a topnotch computer consultant and wants to install Ben's new computer next week. 4. The murderer had his leg amputated last month. 5. Ben met Jack for the first time six months ago. 6. Jack has been in seclusion since the crime. 7. Dan used to drink heavily. 8. Ben and Jeff built their last computers together. 9. The murderer is Jack's brother. They grew up together in Seattle.
Answer: 1. Jack is not the murderer, because he is the brother of the murderer. 2. Dan can't be the murderer since he ran a marathon, and the murderer recently had his leg amputated, and wouldn't be running a marathon of any magnitude that quickly. 3. Ben is not the murderer if he just met Jack, since Jack and the murderer grew up together. 4. This leaves Jeff and Mike. Since Jeff is still alive (he wants to install a new computer next week, present tense) he must be the murderer. Mike also didn't grow up with Jack. It has been determined that Jack, Dan and Jeff are all alive. Ben must also be alive since Jeff plans to install Ben's computer next week. This means that Jeff killed Mike.
Riddle: A blind man is alone on a deserted island. He has two blue pills and two red pills. He must take exactly one red pill and one blue pill or he will die. How does he do it?
Answer: Break each of the pills in half, as you do this pop one half in your mouth and lay the other half aside for tomorrow. When he's done this with all four pills he will have consumed one red pill and one blue pill. And have the same left over.
Riddle: Alice came across a lion and a unicorn in a forest of forgetfulness. Those two are strange beings. The lion lies every Monday, Tuesday and Wednesday and the other days he speaks the truth. The unicorn lies on Thursdays, Fridays and Saturdays, however the other days of the week he speaks the truth. Lion: Yesterday I was lying. Unicorn: So was I. On which day did they say that?
Answer: As there is no day when both of the beings would be lying, at least one of them must have spoken the truth. They both speak the truth only on Sunday. However, the Lion would then be lying in his statement, so it couldn't be said on Sunday. So exactly one of them lied. If the Unicorn was honest, then it would have to be Sunday - but previously we proved this wrong. Thus only the Lion spoke the truth when he met Alice on Thursday and spoke with the Unicorn about Wednesday.