Forever Young Software Puzzles Page

The answers are now included at the bottom of the page

I have put this page here for the interest of 'logical' thinking. Solving these puzzles out on paper or in your head can help you program a little better. Even if you don't program, these puzzles are meant to help your logical thinking.

Please note: These puzzles are no where near the difficulty rating of other puzzles. That is not my purpose. My purpose is to show how to think logically. If you want to solve difficult logical puzzles, there are many sites on the web for this.

See the bottom of this page for the answers.
Please give a difficult rating to each (using the rating I have below) that you answer telling me if it was difficult or not for you.

Each puzzle will be ranked from easy to hard by the following:
(*) - Easy
(**) - Should take you a minute or two
(***) - You might need to draw this one out on paper
(****) - You are pretty good if you get this one

Puzzle #1 (Liar Liar) (09/21/97) (*)
You are walking along a path and come to a fork in the path. There are two directions you could take, the right path or the left path. There is a bench between the two paths with an absolute liar and an absolute truth teller sitting on it. You want to go down the correct path, but without knowing who is the liar and who is the truth teller, what do you ask the two people on the bench? (See the answer)

Puzzle #2 (The Lighter Chicken) (21 Sept 1997) (**)
You are on your way to the market with eight (8) chickens. When you get to the market, the buyer tells you that he will only take all chickens that have the same weight. You know that all but one (1) chicken weighs the same. You take the 8 chickens to the scales in the market, and notice that you only have enough money to use the scales twice. Using these scales only twice, how do you find the lighter chicken? (See the answer)

Puzzle #3 (The Fox, the Chicken, and the Grain) (21 Sept 1997) (***)
You are once again on your way to the market when you get to the river and you find the bridge is out. You see a boat and decide to use it, but you can only carry one item at a time. While carrying one item at a time, how do you get across the river without the fox eating the chicken or the chicken eating the grain? (You have unlimited trip use of the boat) (See the answer)

Puzzle #4 (The Frog in the Well) (21 Sept 1997) (*)
A frog fell in a well that is 21 feet deep. Each day the frog climbs 2 feet, and at night he slides down the slick wall a foot. How many days does it take for the frog to get out? (See the answer)

Puzzle #5 (Vacancy/No Vacancy) (15 Oct 1997) (*)
Three men were on a road trip and decided to rent a motel room for the night. The clerk behind the counter said that there was one room left and that it wasn't very good. The three men decided to take it any way, and asked how much. The clerk asked for $30 and the men each paid $10 and went to the room to rest for the night. When the manager came by the office, he asked how much the clerk had charge the three men for that room. The manager said that was to much and gave the clerk $5 to give back to the three men in the morning. The clerk thought for a minute and said to himself, "I don't know how to divide $5 evenly to the three men." So he put $2 in his pocket and gave $1 to each of the men.
If each of the men paid $9 for the room and the clerk had $2 in his pocket, where did the other dollar go? (See the answer)

Puzzle #6 (3 by 3) (24 Nov 1997) (*)
Hear is a small 3 by 3 box consisting of the numbers 1 through 9. Each set of 3 numbers in any direction equal 15.
      8  1  6
      3  5  7
      4  9  2
What is the "trick" to solving this type of puzzle? i.e.: The "trick" that I am after will work on any odd numbered row/col box (3x3, 5x5, 7x7, ...) and each set of numbers in a straight line will equal the same. (See the answer)

Puzzle #7 (What is the Product) (19 June 2000) (*)
What is the product of the following math problem:

(x-a)(x-b)(x-c)...(x-z) = ???

(where the ... above denotes d through y)
(See the answer)

Puzzle #8 (Three Dimes) (13 May 2008) (**) (Thanks to Karl for this one)
Two Fathers and Two Sons were walking down the street. Something caught their eye, so they stopped to see what it was. Three US Dimes. They chuckled at their find, divided them evenly among them and went on their marry way. How did they do it?
(See the answer)

Answer to Puzzle #1, Liar, Liar :
Ask Liar #1 what would Liar #2 say, then ask Liar #2 what would Liar #1 say. They should both say the same direction. Take the opposite direction.

Answer to Puzzle #2, The Lighter Chicken :
If each chicken has a number of 1 through 8, then do the following:
      123   456             ---   7       8
      \--|--/             /       \--|--/
      | if equal -----/           \  now you have your lighter chicken
      if not equal (and 123 is lighter)
      \----  1       2
      | if equal ----- 3 is the lighter chicken
      \ if not equal, .......

Answer to Puzzle #3, The Fox, Chicken, and the grain :
- take the chicken
- come back (empty handed)
- take the grain
- come back, bring the chicken
- take the fox
- come back (empty handed)
- take the chicken

Answer to Puzzle #4, Frog in the well :
20 days. The frog doesn't fall back down the last day.

Answer to Puzzle #5, Vacancy/No Vacancy :
Puzzling, aint it....... (ask me)

Answer to Puzzle #6, 3 by 3 :
Do you see the pattern?
Start in the top row, middle col. (place the '1', there)
1. Go right one col.
  - if this goes off the table, "drop" to the left most col.
2. Then go up one row
  - if this goes out of the table, drop to the bottom row.
3. If you get to a point, where the next pos will be a filled box, or
  the next move will put off the table at the top right, drop
  down one box from the last number entered.
4. Place the next number there and continue with 1.
Do you see it now?

Answer to Puzzle #7, Product :
  (x-x) = 0, and anything multiplied by zero = zero.
(Did you try figuring it out on paper, or did you catch it right off?)

Answer to Puzzle #8, Three Dimes :
Grandfather = Father
Father = Son and Father
Son = Son
Two Fathers and Two Sons.