There is a barrel with no lid and some wine in it. "This barrel of wine is more than half full," said Curly. "No it's not," says Mo. "It's less than half full." Without any measuring implements and without removing any wine from the barrel, how can they easily determine who is correct?
Tilt the barrel until the wine barely touches the lip of the barrel. If the bottom of the barrel is visible then it is less than half full. If the barrel bottom is still completly coverd by the wine, then it is more than half full.
In a contest, there are four fruits (an apple, a banana, an orange, and a pear) which have been placed in four closed boxes (one fruit per box). People may guess which fruit is in which box. There were 123 participants in the contest. The results are; 43 people guessed none correctly, 39 people guessed one correctly and 31 people have guessed two correctly. How many people guessed three correctly and how many people guessed all four correctly?
It is not possible to only get three correct because the fourth would also be correct. Therefore, the answer would be (123-43-39-31 = 10) 10 people guessed all four correctly.
Find four numbers, the sum of which is 45, so that if 2 is added to the first number, 2 is subtracted from the second number, the third number is multiplied by 2 and the fourth number is divided by 2, then the four numbers so produced are all the same. What are the four numbers?