I only looked at the first "puzzle" and then came back here in some kind of frustration. The "solution" includes apportioning 9 camels to the first son, but 9 isn't 1/2 of 17. Maybe I'm pedantic, but if the solution is allowed to approximate or change the aportionment, then that should be specified in the puzzle statement! I felt tricked. Anyone else?
If someone says they'll pay $8.50 but then they round up and give you $9, you wouldn't say they didn't give you the $8.50 due, right? It's in the $9.
I think implicitly with the inheritance is the assumption that the father is promising at least 1/2, 1/3, and 1/9 of the flock to the respective sons, not the exact fraction. There's a solution where each son gets what's promised, and then a little more.
In addition to the observations in the sibling comments, note that "one half of the camels should go to the eldest heir, one third of the camels should go to the second heir, and one ninth of the camels should go to the youngest heir." -> 1/2 + 1/3 + 1/9 = 9/18 + 6/18 + 2/18 = 17/18ths, not 18/18ths. The will "happens" to be incorrect and fails to allot the full inheritance in exactly the way it needs to be for this to work.
You are correct that it's not solvable in a rigorous mathematical sense as stated.
I added a sentence: “(Warning: This is sort of a trick question, so don’t expect a textbook-style answer!)” I hope that this will prevent others from being similarly frustrated.
What confuses them is the point of the puzzle, to learn that problems can be solved by expanding your perspective and challenging your assumptions. Instead they attack it for being outside their perspective and assumptions.
So I dislike the clue; it undermines the puzzle IMHO. You'll never please everyone!
That's why it's a puzzle and not a textbook word problem. Though maybe word problems should be puzzles more often so that students don't just plug the numbers into a formula and report the result without thinking whether it would be a good solution in the real world.
Note that the integer solution leaves no son cheated out of their inheritance. Everyone gets their apportionment, and a little more.
> (Warning: This is sort of a trick question, so don’t expect a textbook-style answer!)
The part you're missing is that the solution includes the solver gifting a camel to make 18, then taxing back the leftover camel at the end.
Of course, that's still got the same kind of 'but that's not in the rules' issue, but I think the bigger element is that it's not really meant as a "puzzle", but more showing off the unintuitive nature of the results.
Puzzle 1 as written has an error. "with the remaining one-eighteenth of a camel left for the vultures" should be "with the remaining 17/18th of a camel left for the vultures"
I only looked at the first "puzzle" and then came back here in some kind of frustration. The "solution" includes apportioning 9 camels to the first son, but 9 isn't 1/2 of 17. Maybe I'm pedantic, but if the solution is allowed to approximate or change the aportionment, then that should be specified in the puzzle statement! I felt tricked. Anyone else?
If someone says they'll pay $8.50 but then they round up and give you $9, you wouldn't say they didn't give you the $8.50 due, right? It's in the $9.
I think implicitly with the inheritance is the assumption that the father is promising at least 1/2, 1/3, and 1/9 of the flock to the respective sons, not the exact fraction. There's a solution where each son gets what's promised, and then a little more.
In addition to the observations in the sibling comments, note that "one half of the camels should go to the eldest heir, one third of the camels should go to the second heir, and one ninth of the camels should go to the youngest heir." -> 1/2 + 1/3 + 1/9 = 9/18 + 6/18 + 2/18 = 17/18ths, not 18/18ths. The will "happens" to be incorrect and fails to allot the full inheritance in exactly the way it needs to be for this to work.
There's a Wikipedia page about it: https://en.wikipedia.org/wiki/17-animal_inheritance_puzzle
You are correct that it's not solvable in a rigorous mathematical sense as stated.
I added a sentence: “(Warning: This is sort of a trick question, so don’t expect a textbook-style answer!)” I hope that this will prevent others from being similarly frustrated.
What confuses them is the point of the puzzle, to learn that problems can be solved by expanding your perspective and challenging your assumptions. Instead they attack it for being outside their perspective and assumptions.
So I dislike the clue; it undermines the puzzle IMHO. You'll never please everyone!
That's why it's a puzzle and not a textbook word problem. Though maybe word problems should be puzzles more often so that students don't just plug the numbers into a formula and report the result without thinking whether it would be a good solution in the real world.
Note that the integer solution leaves no son cheated out of their inheritance. Everyone gets their apportionment, and a little more.
> (Warning: This is sort of a trick question, so don’t expect a textbook-style answer!)
The part you're missing is that the solution includes the solver gifting a camel to make 18, then taxing back the leftover camel at the end.
Of course, that's still got the same kind of 'but that's not in the rules' issue, but I think the bigger element is that it's not really meant as a "puzzle", but more showing off the unintuitive nature of the results.
Puzzle 1 as written has an error. "with the remaining one-eighteenth of a camel left for the vultures" should be "with the remaining 17/18th of a camel left for the vultures"
Thanks for catching this! I fixed the error.
<https://xkcd.com/169/>