Logic is the art of making truth prevail

– Jean de la Bruyere

Algorithmic thinking is really important as it enhances your thinking skills and can be nurtured with practice. (Refer the previous tutorial to know more about Algorithmic Thinking and try the puzzles before moving on to the solutions.)

 Solutions for the previous problems

Puzzle 3.1 Solution – Find the Murderer

Correct Answer:  Ganpat is the murderer

Explanation: Only one person is speaking the truth.

Scenario 1: Assuming, Ganpat is speaking the truth then Vasu and Shyam both are speaking lie so the true statements would be Ganpat is innocent, Shyam is not innocent and Shyam is not guilty. But the statements are contradicting because Shyam can’t be innocent and guilty at the same time. Therefore, Ganpat is not speaking the truth.

Scenario 2: Assume Shyam is speaking the truth then Vasu and Ganpat both are speaking lie so the true statements would be Ganpat is not innocent, Shyam is innocent and Shyam is not guilty. Since there’s no contradiction, it means Shyam is the only person who is speaking the truth and Ganpat is guilty.

Scenario 3: Assuming, Vasu is speaking the truth then true statements would be Ganpat is not innocent, Shyam is not innocent and Shyam is guilty.Although the statements are not contradicting but here we have two murderes which is not the case here hence this also leads us to the ambiguity and not to the actual solution. Hence only second scenario gives the correct answer which proves Ganpat is the murderer.

Puzzle 3.2 Solution – Half Empty Container

Correct Answer: Tilt the glass until the edge of the water is just touching the rim. Then see whether the highest point of the bottom of the glass is under, over or on the same level as the water.

Explanation: If the water is above the highest point of the bottom, the container has more than 50% water. If it is less than the highest point of the bottom the container is less than 50% of capacity otherwise the container is exactly half empty.

Puzzle 3.3 Solution – Red Eyed Monks


Scenario 1: If there is only one red-eyed monk, he will only see blue eyed monks and know he must be the one with the red eye, so he will leave that night.

Scenario 2: If there are two red-eyed monks, both will see each other and in the next morning, when the other monk doesn’t leave, they’ll figure it out that there must be two red-eyed monks. Since both have seen only one monk with red eyes, both of them will get to know that they themselves must be having red eyes. So they’ll both leave on the second night.

Scenario 3: If there are three red-eyed monks, they will follow the logic above and realize there must be three red-eyed monks after the second night, so all three will leave on the third night.

And so on.

Solving these puzzles is fun, isn’t it? So, wear your logic caps and get ready for your next brain workout:

Algorithmic Thinking
Algorithmic Thinking

Quiz 4.1  – Joye’s Train

Joey is taking the train to the Library. He tells Monica the hour of his train’s departure and he tells Rachel at which minute it leaves. They find out that the train runs at the following services:
0632 0643 0650 0717 0746 0819 0832 0917 0919 0950

Monica then says “I don’t know when Joey’s train leaves but I am sure that neither does Rachel”

Rachel Replies “I didn’t know his train, but now I do”

Monica responds “Now I do as well!”

When is Joey’s train?

Just think about it and post your answer in the comments. I’ll explain this in the next tutorial.

Solution Added – Solution of Joey’s Train puzzle

Quiz 4.2 – Pirates and the Gold Coins

Five pirates of different ages have a treasure of 100 gold coins. They decide to split the coins in the following way : 

The oldest pirate will make a proposal on how to share the coins, and ALL pirates will vote for or against it. If half or more pirates vote for it, then the coins will be shared that way. Otherwise, the pirate proposing will be thrown overboard, and the process will be repeated with the remaining pirates. Assuming that all 5 pirates strategize optimally i.e. they are rational, greedy, and do not wish to die, what will happen?

Just think about the various scenarios and post your answer in the comments.

Solution Added – Solution of Pirates and the Gold coins puzzle

So start thinking and comment answer to the questions asked above and wait for the next post for the solutions.
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Keep Learning. Happy Learning 🙂