Solving Logic Puzzles

1. Solving Logic Puzzles Anora Johnson

2. Logic puzzles can be a lot of fun!

3. Logic puzzles can be a lot of fun!There are many types of puzzles, and many ways to solve them.Classic chart methodSymbolic TranslationMathematical or Picture methods

4. Clark, Daw and Fuller make their living as carpenter, painter and plumber, though not necessarily respectfully. • The painter recently tried to get the carpenter to do some work for him, but was told that the carpenter was out doing some remodeling for the plumber. • The plumber makes more money than the painter. • Daw makes more money than Clark. • Fuller has never heard of Daw. • What is each man’s profession? • Example problem provided by Professor Whitlock

5. Clark, Daw and Fuller make their living as carpenter, painter and plumber, though not necessarily respectfully. • The painter recently tried to get the carpenter to do some work for him, but was told that the carpenter was out doing some remodeling for the plumber. • The plumber makes more money than the painter. • Daw makes more money than Clark. • Fuller has never heard of Daw. • What is each man’s profession? • Clark, Daw, Fuller • Carpenter, painter, plumber • Least, middle, most income

6. A census taker, reporting on a certain community consisting exclusively of young married coupled and their children, stated that:There were more parents than there were children.Every boy had a sister.There were more boys than girls.There were no childless couples.Why was he reprimanded and his report rejected?Example problem provided by Professor Whitlock

7. A census taker, reporting on a certain community consisting exclusively of young married coupled and their children, stated that:There were more parents than there were children.Every boy had a sister.There were more boys than girls.There were no childless couples.P: There are parents in the family.B: There are boys in the family.G: There are girls in the family.

8. A census taker, reporting on a certain community consisting exclusively of young married coupled and their children, stated that:There were more parents than there were children.Every boy had a sister.There were more boys than girls.There were no childless couples.P: There are parents in the family.B: There are boys in the family.G: There are girls in the family.(G v B)  PB  GP  (G v B)

9. (G v B)  PB  GP  (G v B) (G v B)  P / B  G / P  (G v B)

10. (G v B)  PB  GP  (G v B) (G v B)  P / B  G / P  (G v B) These statements contain inconsistent truth values. They cannot all be true at the same time! Thus, the census-taker is shown to have been inaccurate.

11. Among one hundred applicants for a certain technical position it was discovered that ten had never taken a course in chemistry or physics. Seventy-five had taken at least one course in chemistry. Eighty-three had taken at least one course in physics. How many of the applicants had had some work in both chemistry and physics? Example problem provided by Professor Whitlock

12. Among one hundred applicants for a certain technical position it was discovered that ten had never taken a course in chemistry or physics. Seventy-five had taken at least one course in chemistry. Eighty-three had taken at least one course in physics. How many of the applicants had had some work in both chemistry and physics? Example problem provided by Professor Whitlock Answer: 68 Physics No classes Chemistry 7 10

13. More Puzzles!The Smith family, which consists of Mr. And Mrs. Smith, their son, Mr. Smith’s sister, and Mrs. Smith’s father, has for years dominated the community life of Plainsville. At the present time the five members of the family hold among themselves the positions of grocer, lawyer, postmaster, preacher, and teacher in the little town.The lawyer and the teacher are not blood relatives.The grocer is younger than her sister-in-law but older than the teacher.The preacher, who won his letter playing football in college, is older than the postmaster.What position does each member of the family hold?Example problem provided by Professor Whitlock

14. Brown, Clark, Jones and Smith are four substantial citizens who serve their community as architect, banker, doctor, and lawyer, though not necessarily respectively. • Brown, who is more conservative than Jones but more liberal than Smith, is a better golfer than the men who are younger than he is and has a larger income than the men who are older than Clark. • The banker, who earns more than the architect, is neither the younger nor the oldest. • The doctor, who is a poorer golfer than the lawyer, is less conservative than the architect. • As might be expected, the oldest man is the most conservative and has the largest income, and the youngest man is the most conservative. • What is each man’s profession? • Example problem provided by Professor Whitlock

15. Thank you!