Read the article - there are several clues, and bounds can be calculated.
> "If a ship had 26 sheep and 10 goats onboard, how old is the ship's captain?"
What 'clue' did I miss? The only other information is some speculation from a Weibo commenter who thinks that 26 sheep + 10 goats = 7700kgs.
I supposed you could argue that these 5th grade students should know the minimum age required to have a commercial boat licence, but I couldn't tell you that answer for my country (and we don't know that this is a commercial ship, could just be someone taking his livestock for a jaunt around the lake).
In fact my sister ran the data systems for a large trucking company. Her interview questions included "how many ping pong balls will fit in a semi-truck trailer?" She was looking for any kind of process to arrive at an answer. Most folks just flailed around, helpless because the question didn't include the answer in it (like so many test questions in school).
This is all about students being taught by rote, with right answers all neat and pat and solvable. Folks educated like that have a problem with questions like this one. Folks who can 'think outside the box' have no issue at all with uncertainty in the answer.
Similarly, folks posting here who can or cannot see that this question is interesting and solvable (do a degree). No, not by 'an answer' but by a variety of approaches.
I certainly couldn't have done that.
One of the answers was "must be an adult", which still sets bounds. That sounds like a much more reasonable answer for an 11 year old, while it sounds like you think it's reasonable to require a tighter range. Why?
Folks who can "think outside the box" can conceive of a world where "there is no answer to this question" is a meaningful response.