# 3, logic puzzles, which will decide only the most savvy

## Recreation / / December 19, 2019

## 1. Escape from the evil zombies

Grief students arrived for an internship in an abandoned laboratory on a hill. On the first day he was out of curiosity, pulled the lever, which was a picture of a skull and unleashed the evil zombie squad. No time to think: you have to get away from them as soon as possible.

Together with the student run guard, technician and an old professor. The chase they come off, but there is only one path to salvation - old high rope bridge over the endless abyss. The student can run across the bridge in 1 minute, laboratory assistant - 2 minutes. Watchman require 5 minutes, and the professor - as many as 10.

According to the calculations of Professor zombies overtake the fugitives after 17 minutes. Just enough time has a group to cross the chasm and cut the bridge. The matter is compounded by the fact that the surroundings are dark, and the old lamp, which picked up a student, barely shines.

Can you figure out how to transport students, professors, laboratory assistant and a caretaker on the other side of the bridge before they devour evil

zombie?Just remember this:

- Simultaneously, the bridge may be the only two people.
- One of crossing the bridge in the hand have to be light, while others may be waiting in the dark, on either side of the chasm.
- It is necessary to keep within 17 minutes, otherwise the first zombie can set foot on the bridge, while there still are people.
- Cheat useless: it is impossible to jump across the chasm on a rope, you can not use the bridge as a raft to make friends with a zombie or come up with something else.

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1. Student and laboratory assistant instead of going on the safe side. It takes 2 minutes.

2. A student with a lantern alone runs across the side of the lab. It takes 1 more minute, just passed 3.

3. The student gives a lantern keeper and professor, they go on the safe side. It takes 10 minutes, only 13 passed.

4. Technician grabs the lantern in the guard, returns to the side where the student left. It takes 2 minutes, just passed 15.

5. Technician with the student go on the safe side. It takes 2 minutes, just passed 17.

Hooray, all saved! At the last moment the student support cuts the rope bridge, leaving the zombies with anything. Ha-ha!

## 2.Sekretny password

The world enslaved. resistance group - the last hope of humanity. But here's the thing: the despotic rulers seized plucky trio and sent to prison.

Before they were thrown into prison, the boys saw a lot of leaders in the freedom of the numbered corridors. But every exit blocked the electrical barrier. To disable it, you must enter a special code.

One of the squad members are willing to let go, if he can pass the test, and the rest the next morning to feed the salamanders mutants. The boys choose Zoya with her superb logical thinking and equip girlfriend transmitter to hear everything that was happening to her.

When Zoe gone, the members of the squad can hear the echo of her steps in one of the corridors, then the sound stops. A voice announces that she needs to enter the code of three positive integers in ascending order so that the second number is greater than or equal to the first, and the third - is greater than or equal to the second. The girl has three tips, and if she did not guess the code, or to say something more, then again landed in prison.

"The first clue - said the voice - the product of three numbers code is 36". When Zoe asks the second clue, the voice says, that the sum of these numbers is equal to the number of the corridor through which she entered.

There comes a long silence. The guys in prison are sure Zoe remembers a corridor room, but they simply can not know it, but she could not say it out loud. If Zoe could already enter the code, it would have done, but instead she asks the third clue.

Voice announces that the greatest number is found in combination only once. Soon the hum of the electric barrier stops briefly - as prisoners know that Zoe at large. Unfortunately, its transmitter is out of range, so it's all information known to them.

What code you need to enter the children to escape?

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The first clue indicates that it is necessary to calculate all eight possible combinations, of which 36 obtained by multiplying. One of them is true, but it is not clear what it is. Here are a combination of:

corridor number we do not know, so we use the second hint, and calculate the sum of the numbers of each combination. Here's what happens:

All amounts, except for two, are unique. If the corridor number coincides with one of them, Zoe could not ask for a third hint. Since she needed a hint, the corridor should be the same number with a single sum, appearing twice in the list - 13.

Which of the amounts true: 1 + 6 + 6 = 13 or 2 + 2 + 9 = 13? Here help the third clue: "The greatest number is found in combination only once." So, the correct code - 2, 2, 9. With it, the prisoners manage to escape from the prison at night to meet with Zoe and save the rest of the world.

## 3. Parcels for insurgents

Maria is responsible for the supply of important resources on a rebel base, which is located in the heart of enemy territory. At the customs check all parcels on chotkomu Protocol if at the bottom of the box is worth an even number, it is necessary to seal the red cap.

boxes Party have already started to load in transport, when Mary received an urgent message, one of the four boxes marked wrong, but what kind of - is unknown.

The boxes are still on the conveyor belt. Two stand upside down: one contains the number 4, the second - the number 7. The other two boxes are down the bottom: in a black lid, in the second - red.

Maria knows that because of any protocol violation confiscate party and its allies will be in mortal danger. Taking a box to check, she will not be able to get her back on the conveyor and deprive the rebels of vital supplies. Transport will soon be sent - with or without him.

What kind of box or boxes should be removed from the conveyor belt?

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At first it seems that you need to check the back side of each box, but actually Mary, only two are needed.

To understand what is the solution, go back to the minutes. It says that boxes with even numbers should be a red cap. About boxes with odd numbers, there is not a word, so skip the box with the number 7.

And what about the red box with a lid? Do not need to check the number on her bottom? It turns out that there is. According to the protocol, in boxes with even numbers on the bottom should be a red cap. This does not mean that the red lid can only be a box with an even number or a box with a red cover labeled necessarily an even number. The requirement is one-sided, so no need to check a box with red cap.

However, you need to check a box with a black cover, make sure that it mistakenly not covered box with an even number. So, Mary must be removed from the conveyor two boxes: one where the number 4 is written, and the one with the black lid.

If you thought that the red lid can only be on the boxes with an even number, you are not alone. This misconception occurs so often that even has been called "the investigation assertion error."

Its essence is as follows: a certain condition is not only necessary for a particular outcome, but also sufficient. For example, the presence of the atmosphere is necessary that the planet was habitable. But this condition is not sufficient. For example, Venus has an atmosphere, but it does not make it suitable for life.

*Even more interesting problems can be found on YouTube-Channel TED-Ed. Tell me in the comments if you manage to solve the puzzle without hints?*

## see alsoðŸ¤”

- 15 tricky puzzles to practice lateral thinking
- Solve 3 puzzles trick and find out how smart you are
- 11 Soviet tricky puzzles to test logic and wit