The Mistimed Clock!

Andrea’s only timepiece is a clock that’s fixed to the wall. One day she forgets to wind it and it stops.

She travels across town to have dinner with a friend whose own clock is always correct. When she returns home, she makes a simple calculation and sets her own clock accurately.

 
How does she manage this without knowing the travel time between her house and her friend’s?


That's how she manages to set it accurately!
 

Correcting The Mistimed Clock!

 How it was mistimed?

Andrea winds her clock & sets it to the arbitrary time. Then, she leaves her house and when she reaches her friend's house, she note down the correct time accurately. Now, after having dinner, she notes down the correct time once again before leaving her friend's house.

After returning to home, she finds her own clock acted as 'timer' for her entire trip. It has counted time that she needed to reach her friend's house + time that she spent at her friend's house + time she needed to return back to home.

Since, Andrea had noted timings at which she reached & left her friend's house, she can calculate the time she spent at her friend's house. After subtracting this time duration from her unique timer count she gets the time she needed to reach to & return from her friend's house.

She must have taken the same time to travel from her home to her friend's home and her friend's home to her home. So dividing the count after subtracting 'stay time' she can get how much time she needed to return back to home.

Since, she had noted correct time when she left her friend's home, now by adding time that she needed to return back to home to that, she sets her own clock accurately with correct time.

Let's try to understand it with example.

Suppose she sets her own clock at 12:00 o' clock and leave her house. Suppose she reaches her friend's home and note down the correct time as 3:00 PM. After having dinner she leaves friend's home at 4:00 PM.

After returning back to home she finds her own clock showing say 2:00 PM. That means, she spent 120 minutes outside her home with includes time of travel to and from friends home along with time for which she spent with her friend. If time of stay at her friend is subtracted from above count, then it's clear that she needed 60 minutes to travel to & return back from friend's home.

That is, she needed 30 minutes for travel the distance between 2 homes. Since, she had noted correct time as 3:00 PM when she left friend's home, she can set her own clock accurately at 3:30 PM.

The Unfair Arrangement!

Andy and Bill are traveling when they meet Carl. Andy has 5 loaves of bread and Bill has 3; Carl has none and asks to share theirs, promising to pay them 8 gold pieces when they reach the next town.

They agree and divide the bread equally among them. When they reach the next town, Carl offers 5 gold pieces to Andy and 3 to Bill.

“Excuse me,” says Andy. “That’s not equitable.” He proposes another arrangement, which, on consideration, Bill and Carl agree is correct and fair.

How do they divide the 8 gold pieces?

This is fair arrangement of gold distribution! 

Source 

Correcting The Unfair Arrangement!

How unfair the arrangement was?

First we need to know how 8 loaves (5 of Andy & 3 of Bill) are equally distributes among 3.

If each of them is cut into 2 parts then total 16 loaves would be there which can't be divided equally among 3.

Suppose, each of loaves is divided into 3 parts making total 24 loaves available.

Now, Andy makes 15 pieces of his 5 loaves. He eats 8 and gives the remaining 7 to Carl.

Bill makes 9 pieces of his 3 loaves. He eats 8 and gives the remaining 1 to Carl.

This way, Carl too gets 8 pieces and 8 breads are distributed equally among 3.

 
Obviously, Carl should pay 7 gold pieces to Andy for his 7 pieces and 1 gold piece to Bill for the only piece offered by Bill. 
 

Breaking The Safe in 5 Minutes?

Charlie Croker and his team need to break the safe to finish a secret job named "Italian Job" in exactly a five minutes.

They got just one chance and five minutes to finish the job else the local police will be informed.

He got following clues

1st Clue: Exactly one number is perfectly placed.
9 2 5

2nd clue: Everything is incorrect.
9 3 8

3rd clue: Two numbers are part of the code of the safe, but are wrongly placed.
4 9 6

4th clue: One number is part of the code of the safe, but is wrongly placed.
5 8 1

5th clue: One number is part of the code of the safe, but is wrongly placed.
1 2 6 

This should be the process!

To Break The Safe in 5 Minutes...

What was the challenge? 

Re listing all the clues...

1st Clue: Exactly one number is perfectly placed.
9 2 5

2nd clue: Everything is incorrect.
9 3 8

3rd clue: Two numbers are part of the code of the safe, but are wrongly placed.
4 9 6

4th clue: One number is part of the code of the safe, but is wrongly placed.
5 8 1

5th clue: One number is part of the code of the safe, but is wrongly placed.
1 2 6 

------------------------------------------------------------------------------------------------

From 2nd clue, it's clear that 9,3,8 are not part of the code.

Hence correct number suggested by 1st clue must be 2 or 5

Since 9 is not part of the code, the other 2 correct numbers that 3rd clue pointing must be 4 and 6.

If 6 is the part of code, then 1 & 2 are not as 5th clue is suggesting.

And since 2 isn't part of the code then 1st clue must be pointing 5 is correct digit placed in right position.

The 4th clue is also suggesting that 5 is the part of the code but not 1 or 8.

If 5 is correct at it's position as per first clue then 4 and 6 must be occupying other 2 places.

As per 3rd clue position of 4 is wrong, it must be at second place and hence 6 at first place.

Hence the code is 645!