logicHandel has been killed and Beethoven is on the case. He has interviewed the four suspects and their statements are shown below. Each suspect has said two sentences. One sentence of each suspect is a lie and one sentence is the truth. Help Beethoven figure out who the killer is.
Joplin: I did not kill Handel. Either Grieg is the killer or none of us is.
Grieg: I did not kill Handel. Gershwin is the killer.
Strauss: I did not kill Handel. Grieg is lying when he says Gershwin is the killer.
Gershwin: I did not kill Handel. If Joplin did not kill him, then Grieg did.
Who is the killer?

Strauss is the one who killed Handel. You need to take turns assuming someone is the killer; that means everyone's second sentence is a lie. If Joplin was the killer, Grieg's lie mixed with Strauss' counteracts the other. If Grieg was the killer, Gershwin would need to be a killer too. If Gershwin was the killer, Gershwin would need to be a killer too. If Gershwin was the killer, Grieg and Strauss counter each other again, but with Strauss, everything would fit in.

## Similar riddles

See also best riddles or new riddles.

logicshortIf you were to put a coin into an empty bottle and then insert a cork into the neck, how could you remove the coin without taking out the cork or breaking the bottle?

Push the cork into the bottle and shake the coin out.

logicLast week, the local Primary school was visited by the Government School Inspector who was there to check that teachers were performing well in their respective classes. He was very impressed with one particular teacher. The Inspector noticed that each time the class teacher asked a question, every child in the class put up their hands enthusiastically to answer it. More surprisingly, whilst the teacher chose a different child to answer the questions each time, the answers were always correct.
Why would this be?

The children were instructed to ALL raise their hands whenever a question was asked. It did not matter whether they knew the answer or not. If they did not know the answer, however, they would raise their LEFT hand. If they knew the answer, they would raise their RIGHT hand. The class teacher would choose a different child each time, but always the ones who had their RIGHT hand raised.

logicmathshortCan you arrange four 9's and use of atmost 2 math symbols, make the total be 100?

99 / .99

animalcleanlogicA horse is tied to a fifteen-foot rope and there is a bale of hay 25 feet away from him. The horse however is still able to eat from the hay. How is this possible?

The rope wasn't tied to anything.

logicmathshort

Think of a number. Double it. Add ten. Half it. Take away the number you started with. What is your number?

Your number is 5.

logicYou're walking down a path and come to two doors. One of the doors leads to a life of prosperity and happiness, and the other door leads to a life of misery and sorrow. You don't know which door is which.
In front of the door is ONE man. You know that this man either always lies, or always tells the truth, but you don't know which. The man knows which door is which.
You are allowed to ask the man ONE yes-or-no question to figure out which door to go through. To make things more difficult, the man is very self-centered, so you are only allowed to ask him a question about what he thinks or knows; your question cannot involve what any other person or object (real or hypothetical) might say.
What question should you ask to ensure you go through the good door?

You should ask: "If I asked you if the good door is on the left, would you say yes?"
Notice that this is subtly different than asking "Is the good door on the left?", in that you are asking him IF he would say yes to that question, not what his answer to the question would be. Thus you are asking a question about a question, and if it ends up being the liar you are talking to, this will cause him to lie about a lie and thus tell the truth. The four possible cases are:
The man is a truth-teller and the good door is on the left. He will say "yes".
The man is a truth-teller and the good door is on the right. He will say "no".
The man is a liar and the good door is on the left. He will say "yes" because if you asked him "Is the good door on the left?", he would lie and say "no", and so when you ask him if he would say "yes", he will lie and say "yes".
The man is a liar and the good door is on the right. Similar to the previous example, he'll say "no".
So regardless of whether the man is a truth-teller or a liar, this question will get a "yes" if the door on the left is the good door, and a "no" if it's not.

cleanEinstein’slogicFive friends have their gardens next to one another, where they grow three kinds of crops: fruits (apple, pear, nut, cherry), vegetables (carrot, parsley, gourd, onion) and flowers (aster, rose, tulip, lily).
They grow 12 different varieties.
Everybody grows exactly 4 different varieties
Each variety is at least in one garden.
Only one variety is in 4 gardens.
Only in one garden are all 3 kinds of crops.
Only in one garden are all 4 varieties of one kind of crops.
Pears are only in the two border gardens.
Paul's garden is in the middle with no lily.
Aster grower doesn't grow vegetables.
Rose grower doesn't grow parsley.
Nuts grower has also gourd and parsley.
In the first garden are apples and cherries.
Only in two gardens are cherries.
Sam has onions and cherries.
Luke grows exactly two kinds of fruit.
Tulips are only in two gardens.
Apples are in a single garden.
Only in one garden next to the Zick's is parsley.
Sam's garden is not on the border.
Hank grows neither vegetables nor asters.
Paul has exactly three kinds of vegetable.
Who has which garden and what is grown where?

funnylogicshortElmer Johnson went to the hardware store to make a purchase for his house. He asked the store clerk, "How much will one cost?" The clerk thought for a moment and said, "Three dollars." Elmer Johnson, who looked a little puzzled said, "Well then, how much will twelve cost?" "Six dollars," replied the clerk. Elmer Johnson scratched his head and said, "If I were to purchase two hundred, how much would that cost?" "That," said the clerk, "will cost you nine dollars." What was Elmer Johnson buying?

He was buying house numbers.

logicshortWhat country is hidden in the paragraph below?
As defendants, we deny all involvement in the unscrupulous dealings which have come to light in the recent government investigation.

Sweden.

logic
Six jugs are in a row. The first three are filled with coke, and the last three are empty. By moving only one glass, can you arrange them so that the full and the empty glasses alternate?

Move and then pour all coke from second glass to fifth glass.