A Sunday morning puzzle for you.

[Seevio]

Alice and Bob are taken prisoners by an evil logician. They are given one chance to be set free.

Alice and Bob are placed in cells, each have a view of a separate courtyard with trees. There are 20 trees in all, of which Alice sees 12 and Bob sees 8.

Neither prisoner knows how many trees the other sees. But each prisoner is told the trees are partitioned between them: together they see all the trees, but individually no tree is seen by both of them.

They have to figure out the total number of trees, but they are not allowed to communicate with each other.

Each day the logician visits Alice in her cell and asks, “Are there 18 or 20 trees in total?”

Alice has two choices: she can guess or pass. If Alice passes, then the logician visits Bob in his cell and asks the same question.

Bob also can guess or pass. If Bob passes, then the logician retires for the night asks and repeats asking the questions the next day. Both prisoners know the procedure of how the logician is asking questions.

There are consequences to guessing. If either person guesses incorrectly, then they are both trapped forever. If either person guesses correctly, however, then they are both set free immediately.

While they could guess and have a 50/50 chance, is there a way they can escape with certainty?

 

[Kempstonian]

Or Oliver just weighs 40 stone and not the strongest

Weight doesn't come into it. Its all about who is the strongest and that isn't the same as heaviest. Look at any tug of war team and they aren't all really big men (or women).

 

[Kempstonian]

Whilst in the pub, celebrating his son's birthday, the father was asked when was his birthday. He answered thus:

"The day before yesterday I was 25 and the next year I will be 28. This is true only one day in a year."

You tell me, what day is my birthday?

I think the answer is

Spoiler

December 31st

 

[classic33]

I think the answer is

Spoiler

December 31st

You think correctly

 

[Kempstonian]

Alice and Bob are taken prisoners by an evil logician. They are given one chance to be set free.

Alice and Bob are placed in cells, each have a view of a separate courtyard with trees. There are 20 trees in all, of which Alice sees 12 and Bob sees 8.

Neither prisoner knows how many trees the other sees. But each prisoner is told the trees are partitioned between them: together they see all the trees, but individually no tree is seen by both of them.

They have to figure out the total number of trees, but they are not allowed to communicate with each other.

Each day the logician visits Alice in her cell and asks, “Are there 18 or 20 trees in total?”

Alice has two choices: she can guess or pass. If Alice passes, then the logician visits Bob in his cell and asks the same question.

Bob also can guess or pass. If Bob passes, then the logician retires for the night asks and repeats asking the questions the next day. Both prisoners know the procedure of how the logician is asking questions.

There are consequences to guessing. If either person guesses incorrectly, then they are both trapped forever. If either person guesses correctly, however, then they are both set free immediately.

While they could guess and have a 50/50 chance, is there a way they can escape with certainty?

No 😄

 

[ClichéGuevara]

Alice and Bob are taken prisoners by an evil logician. They are given one chance to be set free.

Alice and Bob are placed in cells, each have a view of a separate courtyard with trees. There are 20 trees in all, of which Alice sees 12 and Bob sees 8.

Neither prisoner knows how many trees the other sees. But each prisoner is told the trees are partitioned between them: together they see all the trees, but individually no tree is seen by both of them.

They have to figure out the total number of trees, but they are not allowed to communicate with each other.

Each day the logician visits Alice in her cell and asks, “Are there 18 or 20 trees in total?”

Alice has two choices: she can guess or pass. If Alice passes, then the logician visits Bob in his cell and asks the same question.

Bob also can guess or pass. If Bob passes, then the logician retires for the night asks and repeats asking the questions the next day. Both prisoners know the procedure of how the logician is asking questions.

There are consequences to guessing. If either person guesses incorrectly, then they are both trapped forever. If either person guesses correctly, however, then they are both set free immediately.

While they could guess and have a 50/50 chance, is there a way they can escape with certainty?

Spoiler

Does it relate to their answers on consecutive days? ie, day 1, if she declines, you know she can't see 20.

 

[Seevio]

Spoiler

Does it relate to their answers on consecutive days? ie, day 1, if she declines, you know she can't see 20.

It does indeed. Now all you have to do is work out the specifics.

 

[ClichéGuevara]

It does indeed. Now all you have to do is work out the specifics.

Spoiler

As long as it's not a trick question, they can assume that there are either 18 or 20 trees. He knows she can't see 20 trees, as he can see 8, so she can see 12 or 10. She knows he can see either 6 or 8. On Day two...my head hurts, and I need to think more...I thought I had it.

 

[srw]

Move five matches to balance the scales.
View attachment 516473

No movement needed. It's a 2d representation of a 3d pair of scales seen slightly from above.

 

[Kempstonian]

Wife calls up to her colourblind hubby, "can you bring me down a pair of socks please".

The problem is that all the socks are in a drawer, not paired up. And there are 10 black socks and 10 brown socks and they have logos on them which go above the outside ankle bone.

How many socks does the hubby have to take out of the drawer to guarantee that wifey gets a pair?

This works better if you say red and green socks as colour blind people usually have trouble distinguishing between those colours (so I believe).