Category: Logic puzzles

Three barrels of fruit logic puzzle

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The owner of a fruit orchard has collected three barrels of fruit. There is one barrel of apples, one barrel of pears and one barrel that contains a mixture of apples and pears.

The barrels are all labelled. One label reads “apples”, another reads “pears” and the other reads “apples and pears”. Unfortunately, none of the three barrels are labelled correctly!

You can take out and look at just one piece of fruit from one of the barrels. How can you determine what each of the barrels contain?

Reveal solution

If you choose to inspect a piece of fruit from the barrel labelled “apples and pears”, you can be sure that it will contain either only apples or pears (since you know that all barrels are labelled incorrectly). Looking at the fruit will of course tell you which barrel it is.

The other two barrels will be labelled “apples” and “pears”. If the piece of fruit you looked at earlier was an apple, you can be sure that the barrel labelled “apples” will contain pears and the barrel labelled “pears” will contain both apples and pears.

If however the piece of fruit you looked at earlier was a pear, you can be sure that the barrel labelled “pears” will contain apples and the barrel labelled “apples” will contain both apples and pears.

A hive half full of honey logic puzzle

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At the start of summer, the amount of honey in the bee hive is low. However, the bees work hard and every day, the amount of honey in the hive doubles. On the 30th day of Summer, the hive is full of honey. On what day was the hive half full?

Reveal solution

If it doubles every day, the amount of honey in the hive on any given day would have been half the amount the day before. So if the hive is full of honey on the 30th day of Summer, it would have been half full on the 29th day of Summer.

Crossing the river logic puzzle

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A bee keeper needs to cross a river to collect honey from his bee hives. The only way to cross the river is in a little boat. To complicate matters, the bee keeper is being accompanied by a mouse, a cat and a dog. He can only fit one of these in the boat with him at any one time. Unfortunately, the dog cannot be left alone with the cat, and the cat cannot be left alone with the mouse.

How can the bee keeper get to his bee hives with all three of the animals?

Reveal solution

The bee keeper must first cross the river with the cat (so as not to leave the dog and cat, or cat and mouse unaccompanied together). Upon reaching the other side of the river, the bee keeper can return alone and pick up the mouse. Once the mouse has been taken across the river, the bee keeper must return with the cat (so as not to leave the mouse with the cat) and take the dog across. The bee keeper then return one final time to collect the cat.

The lying bee and the truthful bee logic puzzle

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There were two bees, Apollo and Buzz. Apollo said to Buzz, “I always tell the truth”. Buzz responded, “I always lie”.

One of these statements is correct. Which one?

Reveal solution

The statement by Buzz “I always lie” is an example of the liar paradox. If the statement were to be correct, it would contradict itself (Buzz cannot always lie if he tells the truth about always lying). Thus, given one of these statements was indicated to have been correct, it must be Apollo’s.

Bee-tween the trains logic puzzle

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Two trains, 200 miles apart, are heading towards each other. Both trains are going at a speed of 100 miles per hour. A little bee starts flying from one train towards the other. The bee is flying at an amazing speed of 150 miles per hour! When the bee reaches the other train, it turns around and flies back to the first train. It keeps going back and forth between the two trains until they crash into each other! Thankfully, the people on the trains and the little bee are unharmed.

In total, how far did the little bee fly between the two trains before they crashed?

Reveal solution

Finding the solution to this puzzle is simpler than it first appears. Since the trains are both travelling 100 miles per hour towards each other, their relative speed is 200 miles per hour. It will therefore take one hour to cover the 200 mile distance between them. During this one hour, the little bee will have travelled 150 miles.