CS2984: Introduction to Problem Solving
Homework Assignment 9

Due at 11:00pm on Tuesday, October 16
50 Points

10/11: Revised wording on questions 7-10. Changes are in () or [].

Here are the problems for Homework 9.

For the first six problems, you must indicate what numbers or values best fill in the blanks. You must also provide a complete description for the pattern. 

  1. 13  18  20  19  24  26  25  30  32
    ___ ___ ___ 
  2. 4  14  21  26  36  43  48  58  65
    ___ ___ ___ 
  3. 7  3  4  8  4  5  10  6  7  14  10  11  22
    ___ ___ ___
  4. d a a e c c f e e ___ ___
  5. c i o d j p e k q ___ ___
  6. d g h e j k f m n ___ ___

The following four problems are exercises in lateral thinking. Be assured that each problem has an answer, and once discovering (or hearing) the answer, most people would be satisfied that it is "correct." They are all similar in that they tend to be difficult due to natural "blind" spots in comprehension. Answers should not require any bizarre interpretation of the question, nor any strained or unusual circumstances in the explanation.

  1. Acting on an anonymous phone call, the police raid a house to arrest a suspected murderer. They don't know what he looks like but they know his name is John and that he is inside the house. The police bust in on a carpenter, a lorry driver, a mechanic and a fireman all playing poker. Without hesitation or communication of any kind, they immediately arrest the fireman. How do they know they've got their man? [Hints: The precise occupations are not relevent. A house is a house.]
  2. How could a (normal, human) baby (accidently!) fall out of a twenty-story building onto the ground and live?
  3. There are three cookies in a box. Three children each take one of the cookies (each gets a whole cookie). How can it be that one cookie is left in the box?
  4. A woman has five (living, normal, healthy) children. Half of them are boys. How can this be?