13 decks of cards have been mixed. What is the minimum number of cards that must be taken out from the above-mixed cards to guarantee at least one 'four of a kind?
An express train takes 3 seconds to enter the tunnel which is 1 km long.
If it is travelling at 120 km an hour, how long will it take to pass completely through the tunnel?
What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?
A man looks at a painting in a museum and says, “Brothers and sisters I have none, but that man’s father is my father’s son.†Who is in the painting?
The day before the 1996 U.S. presidential election, the NYT Crossword contained the clue “Lead story in tomorrow’s newspaper,” the puzzle was built so that both electoral outcomes were correct answers, requiring 7 other clues to have dual responses.
