Brainteasers: April 2007

Compiled by Julianne Scibetta

Thank you to Matthew Winkler, who gets a gold star for this month's answers. A shout out to Bruce Epps for the January/February round.

Click here to see last month's brainteasers: http://www.learningassistance.com/2007/march/index.html#brainteasers

Solutions to March 2007

  1. Bird-watching. Three birds were seen by one person each, three were seen by each unique pair (Abel-Mabel, Abel-Caleb, and Mabel-Caleb), and one was seen by all three. So seven birds were seen in all, and each person saw a total of four. Hence, all of the birds Caleb saw were yellow. These four birds are: (1) the one Caleb saw alone, (2) the one Caleb saw with Abel, (3) the one Caleb saw with Mabel, and (4) the one all three saw together. This accounts for both of the yellow birds Abel saw, and two of the three yellow birds Mabel saw. The third yellow bird Mabel saw could not have been the one Abel and Mabel saw together, because Abel only saw two yellow birds; so the third yellow bird Mabel saw must have been the one she saw alone.

    So five yellow birds were seen (the one Mabel saw, the one Caleb saw, the one Abel and Caleb saw, the one Mabel and Caleb saw, and the one all three saw), and two non-yellow birds were seen (the one Abel saw and the one Abel and Mabel saw) by the group.


  2. Number Puzzle. ((7+7) ÷ 7) + 9 = 11.


  3. Answers:
    1. Early to bed, early to rise.
    2. Don't put off until tomorrow what you can do today.
    3. All work and no play makes Jack a dull boy.
    4. A fool and his money are soon parted.

April's Questions

Use your common sense.
  1. A dog can run fifty miles in a day. How far could he run into a 120 square mile forest in a day?


  2. The human body holds nine quarts of blood. Suppose you were alone in the desert and accidentally cut a major artery. If you bleed at one cup per minute, how long will it take you to bleed to death?


  3. A train leaves from New York City heading toward Los Angeles at 100 mph. Three hours later, a train leaves from Los Angeles heading toward New York City at 200 mph. Assume there's exactly 2000 miles between Los Angeles and New York City. When they meet, which train is closer to New York City?


  4. And for those of you who need a different kind of mental exercise: Can you place six X's on a Tic Tac Toe board without making three-in-a-row in any direction?