The task with the thread when hiring at Apple, Google and Microsoft will be mastered only by people sharpened for success.

At the interview, the applicant can often hear some completely unexpected question that can knock off the rut. Many people just wonder why they are being asked to do something. interviewingIf such tasks have nothing to do with future work. And it is especially sad when the answer to such a question can not be found.



The fact is that with the help of tasks, employers (or their representatives) are trying to either find the smartest workers, or simply create a difficult situation for a potential employee to assess how he will find a solution. And how fast he can handle it.

So today's editorial office. "Site" Ask readers to solve a couple of problems that come across in interviews. See if you can make up your mind to convince everyone in the interview that you're smart.



Interview tasks

1. From the conditions of the first problem, we learn that there are two ropes, each of which burns in exactly 60 minutes. With these ropes and a box of matches, we need to measure exactly 45 minutes of time. How do you do that?
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2. To solve the second problem, you need to find out what the probability is that a car will pass you in 20 minutes. At the same time, it is only known that in the area where you are, one car passes by in 10 minutes with a probability of 20%.
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3. The third problem in different interpretations is found in job interviews, even at Apple, Google and Microsoft. The essence of the problem is simple: there are two doors, it leads to victory, and the second to defeat. There is a guard at every door, one always telling the truth and the other always lying. I don't know which one. With what question can you immediately know which door will lead to victory? Keep in mind that there is only one question to ask. And only one guard.
   
   
   
   
   
   

Tips and solutions

1. At first it seemed to me that one piece of rope could be folded fourfold, cut off the fourth part so measured, and set the remaining 75% of the rope on fire. But the official response surprised. The fact is that you need to set the first rope on fire on both sides, and the second rope at the same time should be set on fire on one side. As a result, the first rope will burn in 30 minutes. But the second rope at that time will remain half (also 30 minutes). Now we set fire to the second end of the second rope. In 15 minutes, it will burn out completely. So we get 30 + 15 = 45 minutes.
   
   
2. We immediately understand that the probability of a car passing by in the next 10 minutes is 0.2. In this case, the probability that the car will not pass here in 10 minutes: 1 – 0.2 = 0.8. Therefore, the probability that a car will not pass next to a person in the next 20 minutes is already: 0.8 × 0.8 = 0.64. Then the probability of driving in 20 minutes: 1 – 0.64 = 0.36. Or 36%.
   
   
   
   
3. The right question in this situation is: “What door does the second guard think leads to defeat?” If you ask this question to a true guard, he, knowing the cheating neighbor, will point to the “victory” door. If you ask a cheating guard, he will also point to the right door. Or perhaps you would ask another question?

Also solve our problems, which we published the other day. And share your answers and comments in the comments.