The document contains 10 puzzles or logic problems with varying levels of complexity. The puzzles involve subjects like passwords, escape scenarios, weighted objects, math equations, visual patterns, shapes, statements from multiple individuals, road routes, and eggs in a nest over time. The puzzles require logical thinking to determine the right answers or solutions.

1. 10 Puzzles
by Fabrizio Valerio Covone

2. Puzzle 1
A spy wants to enter in a top secret building, but the guard at the
entrance asks everyone a password.
For this reason the spy hides out and wait for someone, so he can
have a peek. A person comes and the guard says:
“Wait! If I say six which is the password?”
“Three!”
“Ok, come in.”
The spy thinks: “mmh… I guess how it works…” But to be sure he
keeps hiding and wait for another person. Another one comes:
“Hold on! If I say twelve which is the password?”
“It’s six!”
“Ok, come in.”
“Ok I got it” the spy thinks and try enter, but obviously is stopped by
the guard asking the password:
“Hey you, wait! if I say eight which is the password?”
“I bet it’s four!”
The guard in second takes his gun and shoots down the spy.
Which was the right answer?

3. Puzzle 2
A spaceship has a failure and auto-destruction activates itself. The 20 people crew
have exactly 13 minuets to escape from such a deadly trap.
But the safety escape pod is capable to carry a total of 4 people and there aren’t any
space suites. Furthermore, a trip to the nearest planet and back takes 3 minutes.
How many people will survive?

4. Puzzle 3
An explorer finds a secret chamber in a pyramid. Inside the chamber there are 7
identical metal bars and a rusty 2 scale pans balance.
An inscription on the wall says that only 1 of the metal bars is made of gold the other
ones are made of pyrite (a metal similar to gold but slightly heavier and worthless).
The explorer wants to take only the gold bar, but he is very lazy and wants to figure it
out doing as less weightings as possible.
Which is the minimum number of weightings?

5. Puzzle 4
A, B, C and D are single-digit numbers.
The following equations can all be made with these numbers.
Find the values of each digit.
A+B=D
B−A=C
2×C=8
D÷3=2

6. Puzzle 5
Have a look at this wonderful example of modern art.
How many squares can you see?
Be sure to count overlapping squares separately.

7. Puzzle 6
Only one of these pictures can be drawn with one line without lifting your
pen from the paper or retracting any lines.
Which one is it?

8. Puzzle 7
During lesson break someone ate all classroom snacks, interrogated by the
teacher the 3 students in the classroom gave the following statement:
A:“C is lying, I saw him eating the snacks.”
B: “I didn’t see anything.”
C: “B is a liar, I saw him taking the snacks from the bags. ”
Only one of them is saying the truth. So, who ate the snacks?
A B C

9. Puzzle 8
Three of the four shapes below can be combined to form a square. Which one
isn’t used?
Feel free to rotate the shapes.
A B
C
D

10. Puzzle 9
Joe forgot his wedding anniversary,
but thanks to his brand new
smartphone he got a reminder just
1 hour before his wife’s alarm rings.
Now he has to buy a present at the A
jewelry, to take the breakfast at the B
restaurant and to rent her favorite
movie before she wakes up.
C
For this reason he has to to do the
shortest travel possible. Be careful,
only grey roads at the borders are
two-way. While blue roads are one-
way following arrows direction.
Which is the shortest trip D
sequence?

11. Puzzle 10
On a tree there is a nest with ten eggs. On winter time a strong wind gust
shook the nest and two eggs fell down. Furthermore during an heavy spring
rain, a cracked branch fell and cracked three eggs.
Assuming that no other accidents happen, how many eggs are left at the end
of the summer?