Brainstorming Puzzles Set 10 – Identify The Identical Sisters | The Missing Fish

The best way to predict the future is to create it.

– Abraham Lincoln

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 9.1 Solution – Guess The Shirt Color

Correct Answer:  Mr. Blue is wearing a red shirt, Mr. White is wearing a blue shirt and Mr. Red is wearing a white shirt.

Explanation: Mr. Blue could only be wearing a white or red shirt and we know that there is already someone else wearing the white shirt (since Mr. Blue said one dialogue and the man wearing the white shirt said another) so Mr. Blue could only be wearing the red shirt.

Mr. White could have only been wearing a red or a blue shirt, but red shirt is already worn by Mr. Blue, so Mr. White would be wearing a blue shirt.

Therefore, Mr. Red would be wearing a white shirt.


Puzzle 9.2 Solution – Crossing The Bridge

Explanation: A and B (2 min) cross first using up 2 minutes
B (2 min) comes back making it 4 minutes
C and D (10 min) cross making it 14 minutes
then A (1 min) crosses back over making it 15 minutes
And finally, A and B (2 min) cross together, for a total of 17 minutes.


Puzzle 9.3 Solution – Count The Pets

Correct Answer: There is one dog, one cat, and one parrot.

Explanation: All except two were dogs and all except two were cats. So two animals were not dogs and two animals were not cats. One of the “not dogs” could have been a cat, and one of the “not cats” could have been a dog. Combine this with the fact that all except two of the pets were fish and we have the result:

One dog, one cat, one fish – three animals at the Pet Show!


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 10.1  – Identify The Identical Sisters

There are three identical sisters. The oldest by minutes is Sarah, and Sarah always tells everyone the truth. The second eldest is Sue, and Sue always tells everyone a lie. Sally is the youngest of the three. She might sometimes lie and sometimes tell the truth.

Sam, an old family friend, came over one day and asked each one of them a single question.

He asked the girl that was sitting on the left, “Which sister is in the middle of you three?” and the answer the girl said, “Oh, that’s Sarah.”

He then asked the sister in the middle, “What’s your name?” The girl said, “I’m Sally.” 

He turned to the girl on the right, then asked, “Who is that in the middle?” The girl said, “She is Sue.”

Listening to all the answers, Sam was able to figure out who was who.

Can you figure it out as well?

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

Solution Added – Solution of “Identify the identical sisters” puzzle


Quiz 10.2 – The Missing Fish

Two fathers took their sons fishing. 

Each man and son caught one fish, but when they returned to camp there were only 3 fish. How could this be?

(None of the fish were eaten, lost, or thrown back.)

Just think about it and post your answer in the comments.

Solution Added – Solution of “The Missing fish” 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 🙂