We propose to play the following game for two players: Starting from scratch, each player in his turn adds 4 or adds 7 to the result that the other player has obtained. If the result that a player gets in his turn ends in two zeros the player wins. Is there any strategy to win the game?
When the teacher has corrected the first six exams in the class, the average grade is 8.4 points. When correcting the seventh, the average score rises to 8.5 points. What grade did you get the seventh exam? Solution The seventh grade is 9.1. The total of the first 6 exams is: 8.4 × 6 = 50.4.
From the page www.dow.com we get an interesting puzzle with a very simple question, although answering it will not be so simple. What is the result of this equation? Thanks to Raúl García for the contribution. Solution The solution to the equation is 7,000,000,000 which represents the number of inhabitants of the planet in 2011.
Three people decide to play to throw coins and see if they coincide in face or cross. Each one throws a coin and the one that does not match the other two loses. The loser must double the amount of money that each opponent has at that time. After three games, each player has lost once and has 240 cents.
Find a number consisting of two digits: AB which is the prime number that is in the CD º position of the list of prime numbers and which is read backwards: BA is the DC º prime number written in reverse: CD is the result of multiplying A * B. It is the case that both A and B and A B are Capicúas numbers (or palindromes) if we express them in binary.
The image shows an incomplete geomagic square. Similar to the magic squares in which when adding all the numbers of a row, column or diagonal we always get the same result, in this geomagic square if we put all the pieces of a row, column or diagonal together we always get the figure that appears on the sidelines
The director of the bank branch of my town is a somewhat peculiar person. So much so that it has engraved the code of the bank's safe on the inside of the lid of a curious wooden box with a sliding lid that does not hide, but rather exhibits on its table. To protect the code from prying eyes, that box also contains a deadly venom snake that inevitably bites everyone who opens the box while also passing over any protection such as gloves.
There is a regular train line that connects my town with the city. Trains leave every 10 minutes from both ends of the route that lasts exactly one hour. The operating hours of the service go from 07:00 in the morning until 21:00 at night, which is the time at which the last train leaves each of the terminal stations.
We are facing one of the typical hobbies in which one word becomes another by changing a single letter at each step. In this case, a phrase will help us find each of the words. I am a drink. Change a letter and I become a tree. Change another letter and I become the floor of your house.
This phrase has no consonants. Substitute the N of the previous sentence for a number expressed in letters that makes the phrase false. Solution To ensure that the statement is false, we must look for a number that expresses the number of consonants in the sentence including the new word introduced.
In a store there are 6 barrels containing 8, 13, 15, 17, 19 and 31 liters of oil or vinegar. We know that a liter of oil costs twice as much as vinegar. A customer buys € 1400 of oil and € 1400 of vinegar, so that he takes all the barrels except one. What barrel was left in the store?
A baby whale weighs as much as 3 elephants or equal to 5 hippos. A hippo weighs as much as a rhinoceros or as 2 giraffes. A giraffe weighs as much as 4 zebras or 13 chimpanzees. How many chimpanzees will I need to match the weight of the baby whale? Solution 1 baby whale = 5 hippos 1 hippo = 2 giraffes 1 giraffe = 13 chimpanzees 1 baby whale will be = 5 x 2 x 13 = 130 chimpanzees
A teacher uses an hourglass that lasts exactly five hours to measure the class time that begins at 09:00 in the morning. At a time when the teacher is on his back writing on the board, a joker student turns the clock. After a while the same student, regretted, returns it to its original position when it is 11:30.
George and Marge married after their respective divorces. Both had children from their previous marriages. Currently 9 children live with them. George is the father of 4 of them and Marge is the mother of 6. How many children have had fruit from their current marriage? Solution If they had not had children in common, they would currently live with 4 + 6 = 10 children.
Antonio married Beatriz. After a time of happy marriage, they had a baby. Years later, that baby grew up, married his partner and they had a daughter named Cristina. The last names of the 5 family members mentioned are, in alphabetical order: González Pérez González Rodríguez Pérez González Pérez Rodríguez Rodríguez Pérez What is the sex of Antonio and Beatriz's son?
Alberto has to go to the city to do some shopping and then come back home. I wanted to make the trip at an average of 60Km / h but due to traffic, the average speed of the outbound trip has been 30Km / h. What average speed should I do on the return trip to finish the entire trip at an average speed of 60Km / h?
A cyclist leaves his house riding his bicycle. The two wheels of the bicycle are identical and no skidding occurs during the ride. After a couple of hours he returns home. Which of the two wheels has turned the most during the ride? Solution The front wheel travels a longer path so it turns more than the rear.
Alberto and Benito are two brothers who go to school every day by bus as they travel ten times faster than they walk. In the street where they live there are two stops on the same bus line and although they live together, Alberto always goes to the stop on the right that is closer and Benito always goes to the stop on the left, in the same sense in which the bus circulates.
In a public parking lot where yellow, white and red cars were parked, there were twice as many yellow cars as white and twice as white as red. Some thieves entered the parking lot and stole several cars. They stole as many yellows as reds left intact. The red cars without stealing were three times more numerous than the stolen whites and there were as many white cars as red without stealing.