TEST: can you solve the problems from interviews in cool American companies

The chances that the first measurement we will immediately come across the same spoiled pill is one in five. This means that you need to weigh pills from several cans at the same time. If you take one tablet from each jar and put them all on the scales, you get the following amount: 10 + 10 + 10 + 10 + 9 = 49 grams. But this is understandable even without weighing. In this way, it is impossible to find out which of the cans contains the damaged pill. You need to act differently. First, let's assign each jar a serial number from one to five. Then put on the scales one tablet from the first can, two from the second can, three from the third, four from the fourth, five from the fifth. If all pills were of normal weight, the result would be: 10 + 20 + 30 + 40 + 50 = 150 grams. But in our case, the weight will be less just by the number of grams that corresponds to the number of the jar with spoiled tablets. For example, we got a weight of 146 grams. 150 - 146 = 4 grams. So the spoiled pills are in the fourth can. If the weight is 147 grams, then the spoiled pills are in the third can. There is also another solution. We weigh one tablet from the first can, two from the second, three from the third, four from the fourth. If the weight is less than 100 grams, then the number of missing grams will indicate defective packaging. If the weight is exactly 100 grams, then the spoiled pills are in the fifth jar.

The ants will not bump into each other either when everyone is moving clockwise or when everyone is counterclockwise. In other cases, the meeting is inevitable. Each ant can go in two directions, there are three ants in total. Hence, the number of possible combinations of directions is as follows: 2 × 2 × 2 = 8. Of all the combinations, only two satisfy the condition that they will not meet. We recall the formula for calculating probabilities: p = m ÷ n, where m is the number of outcomes that favor the event, and n is the number of all equally possible outcomes. Let's substitute our numbers: 2 ÷ 8 = ¼. This means that the chance to avoid a collision is one in four.

It is necessary to simultaneously set fire to the first rope from both ends, and the second rope from only one end. These ropes must not touch. The first will burn out in 30 minutes - this is exactly how much the tips set on fire on both sides will meet. When this happens, the second rope will only have a length of 30 minutes. You need to quickly set fire to it from the second end, then the lights will meet in 15 minutes, and only 45 will pass.

Solution 1. You need to pour 5 liters of water into a large bucket, then pour 3 liters of water from it into a small one. The large bucket will leave 2 liters of water. Now pour out 3 liters of water from a small bucket and pour into it the 2 liters that remained in the large bucket. We refill the five-liter bucket to the brim, pour one liter out of it into a three-liter bucket, which already contains two. This means that 4 liters will remain in the large bucket, which we needed.Solution 2. We fill a three-liter bucket to the brim, pour it entirely into a five-liter one. Then we repeat these steps again until the five-liter bucket is filled to the brim, and there is no 1 liter left in the small one. Now we pour out the water from the five-liter bucket. Pour 1 liter into a XNUMX liter bucket, fill a small bucket to the brim, pour into a large one. Voila!

The trick is that all the boxes are labeled incorrectly. This means that each is not what is indicated on the label. That is, the box labeled "Apples + Oranges" can contain either only apples or only oranges. We get the fruit out of there. Let's say we come across an apple. So this is a box of apples. There are two boxes left: labeled "Apples" and labeled "Oranges." Remember that the information on the labels is incorrect. This means that the box marked “Oranges” can contain either apples or a mixture of fruits. But we've already found the apples. Hence, this box contains a mixture of fruits. The remaining box labeled "Apples" contains oranges. Similar reasoning would allow us to solve the problem if we took an orange out of the box labeled "Apples + oranges".

Regardless of whether these tasks were easy for you or not, ForumDaily is always ready to help you find a job in the USA. Read our heading "Work"to see current vacancies, learn how to write an effective resume, prepare for an interview, and just keep abreast of all the new developments in the American labor market.