Because Oct 31 represents the octal (base 8) number 31, which, when converted to decimal, is 25. Dec 25 is short for Decimal 25, thus the two are equal.
I was visiting a friend one evening and remembered that he had three daughters. I asked him how old they were. “The product of their ages is 72,” he answered. Quizzically, I asked, “Is there anything else you can tell me?” “Yes,” he replied, “the sum of their ages is equal to the number of my house.” I stepped outside to see what the house number was. Upon returning inside, I said to my host, “I’m sorry, but I still can’t figure out their ages.” He responded apologetically, “I’m sorry, I forgot to mention that my oldest daughter likes strawberry shortcake.” With this information, I was able to determine all three of their ages. How old is each daughter?
The house number alone would have identified any of these groups. Since more information was required, we know the sum left the answer unknown. The presence of a single oldest child eliminates “2 6 6”, leaving “3 3 8” as the only possible answer.
Two legs sat upon three legs with one leg in his lap. In comes four legs, grabs one leg, and runs off with him. Up jumps two legs, grabs up three legs, throws it after four legs, and makes him bring back one leg.
Three philosophers are taking a nap under a tree. While they’re asleep, a small boy smears their noses with red berries. When they awake, they each begin to laugh, thinking the other two are laughing at each other.
But then one philosopher stops laughing, realizing his nose is red too. How did he come to this conclusion?
Let’s call the philosopher’s A, B and C. A reasoned that B was confident his nose wasn’t red. If B saw A’s nose wasn’t red, he would be surprised that C was laughing, because C would have nothing to laugh at. But B wasn’t surprised, therefore, A correctly reasoned his nose was smeared.