Optical Illusion: A cat is hiding in plain sight in the backyard. Only the most observant eyes can spot the cat in 7 seconds. Can you? Test your eye power now!
A chess tournament is taking place on knock-out terms (the one who loses the match is out of the game).
(a) If 10 matches are played in total, how many players participated?
(b) If 20 players took part in the tournament, how many matches were played?
There are five people. One of them shot and killed one of the other five.
We know following clues:
1. Dan ran in the NY City Marathon yesterday with one of the innocent men.
2. Mike consider being a farmer before he moved to the city.
3. Jeff is a top notch computer consultant and wants to install Ben 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.
Consider yourself to be a famous detective "Sherlock Homles", Can you find the killer?
One evening there was a murder in the home of a married couple, their son and daughter. One of these four people murdered one of the others. One of the members of the family witnessed the crime.
The other one helped the murderer.
These are the things we know for sure:
1. The witness and the one who helped the murderer were not of the same sex.
2. The oldest person and the witness were not of the same sex.
3. The youngest person and the victim were not of the same sex.
4. The one who helped the murderer was older than the victim.
5. The father was the oldest member of the family.
6. The murderer was not the youngest member of the family.
In 2011, people playing Foldit, an online puzzle game about protein folding, resolved the structure of an enzyme that causes an Aids-like disease in monkeys. Researchers had been working on the problem for 13 years. The gamers solved it in three weeks.
