Logic Riddles

Question: A person has one lion, one lamb and a bundle of grass. He wants to cross a river but there is only one boat and it can't sustain the weight of more than two articles at time. Also, he has to make sure that the lion doesn't eat the lamb and the lamb doesn't eat the grass. How will he get to the other side of the river with all three intact?

Question: You fill up a bathtub with water and you have a teaspoon, tablespoon, and fourth cup. What is the fastest way to empty the bathtub?

Question: You are a prisoner. The only way to escape the prison is to walk down a very long hallway that takes 2 hours to get through. Guards come out of a door halfway down the hall every hour and take any prisoners walking out back to the prison and escort any visitors out of the prison. The guards cannot tell the difference between prisoners and visitors.

How do you escape?

Question: What single line can you add to the following statement to make it true?

5+5+5=550

Question: If you toss a coin ten times and it lands heads up every time, what are the chances it will land heads up if you toss it again?