Friends on a Walk
I start my homework with warm-up puzzles.
Puzzle. Two friends went for a walk and found $20. How much money would they have found if there were four of them?
The answer, of course, is $20. The number of people doesn’t change the amount of money lying around. Even ChatGPT gave this answer. Duh!
My hope was to catch them not paying attention and mindlessly multiply to get $40.
To my surprise, some of them answered $80. The ‘them’ in the problem is not specified. It appears that they read the puzzle as if they found one 20-dollar bill, and them was referring to bills.
One student wrote a thoughtful reply: Having more friends most likely wouldn’t change the amount of money found, considering the amount of money is independent of the number of people, meaning the friends would still find $20. However, with double the people, they may find more money in other locations. There is also a chance that the 2 extra friends would make the group walk a different path, meaning they wouldn’t find money at all.
Share:
Ivan:
More friends equals more viewpoints. Some of them might see that the big money are not on the sidewalk, but at the edge of the sidewalk, i.e. in the buildings, so she can suggest a building-related business.
Viepoints are important. Many Europeans think America is in the West, but the first European to discover America (Leif Erikson) discovered it in the South.
1 October 2025, 11:34 pmAndreas:
If Alice and Bob joined Charlie and Eve for the walk then they might have been more immersed in their discussion, causing them to not notice the money.
Also, if Alice is the one who dropped the $20, then the money would not have been there for them to find if she joined the others instead of going for the walk earlier.
And obviously, if they had waited for Bob to get ready, they would have departed later and someone else might have picked up the money first.
So considering everything I think it’s safe to say that they would not have found any money if there were four of them. It should be easy to verify – just ask all four of them to go for a walk again and see how much money they find.
2 October 2025, 1:48 pm