Logic Puzzles 5 [With Answers]

Puzzle-1:

You work at a fruit factory. 

There are 3 crates in front of you. One crate contains only apples. One crate contains only oranges. The other crate contains both apples and oranges. 

And each crate is labeled. One reads "apples", one reads "oranges", and one reads "apples and oranges".
But the labeling machine has gone crazy and is now labeling all boxes incorrectly.
If you can only take out and look at just one of the pieces of fruit from just one of the crates, how can you label ALL of the crates correctly?

Answer: Take a piece of fruit from the "apples and oranges" crate. If it's an apple then you know that is the "apples" crate since ALL THE CRATES ARE LABELED INCORRECTLY. This means the crate marked "apples" must be "oranges" and the crate marked "oranges" must be "apples and oranges".

Puzzle-2:

A man is caught on the King's property. He is brought before the King to be punished.

The King says, "You must give me a statement. If it is true, you will killed by lions. If it is false, you will be killed by trampling of wild buffalo."

But in the end, the King has to let the man go.

What was the man's statement?

Answer: "I will be killed by trampling of wild buffalo."

If you think about it carefully: the King can't say it is true, because if so the man should be killed by the lions. But if he is killed by the lions, then his statement would be false, and so should have been trampled by buffalo.

So the King can't tell if it is a lie or truth, so decides to just let him go.

Puzzle-3:

A man works on the 10th floor and always takes the elevator down to ground level at the end of the day.

Yet every morning, he only takes the elevator to the 7th floor and then walks up the stairs to the 10th floor, even when in a hurry.

But he will go all the way to the 10th floor when others are in the elevator with him or on a rainy day.

Why?

Answer: He is too short to reach the "10" button.

But when others are with him, he can ask them to push the button for the 10th floor. 

And on a rainy day he has an umbrella, so he can push the button using that.

Puzzle-4:

There are five gears connected in a row, the first one is connected to the second one, the second one is connected to the third one, and so on.

How much faster would the last gear be if the second gear was twice the size of the first gear, and all the other gears were the same size as the first gear?

Answer: The last gear would be the same speed.

Puzzle-5:

There are three people (Alex, Brook and Cody), one of whom is a knight, one a knave, and one a spy.

The knight always tells the truth, the knave always lies, and the spy can either lie or tell the truth.
Alex says: "Cody is a knave."

Brook says: "Alex is a knight."

Cody says: "I am the spy."

Who is the knight, who the knave, and who the spy?

Answer:

Alex is a Knight

Brook is a Spy

Cody is a Knave

Brook is not the knight, since if he is, then Alex would also be the knight.

Cody is not the knight, since his statement would then be a lie. 

Therefore Alex is the knight. Hence Cody is the knave, and Brook is the spy.