There are 125 sheep and 5 dogs in a flock. How old is the shepherd? / Math Education

At least in the boat problem one can give an interval estimate:)

Seriously, though, this is interesting stuff. I thought about writing a post on 'different assumptions' like this, like when you have explained to a student how to calculate the molecular mass of a compound, show them the very rudiments of mass spectrometry theory and watch them try to reconcile the idea of a structured molecule (or whatever it is called in salts) with the idea of just totalling the nuclons and dividing by the charge. I had problems with it when I had to read about it.

Or there's another case of diatoms' shells inheritance, compared to Mendelian genetics.

If anyone has an idea of another 'similar-but-not-similar' pair of problems, please let me/us know.

Yes, I agree. It shows children are trying to guess the teacher's password and are not doing math. Interestingly, when I asked my son this question he said you couldn't find the answer. When I asked how he knew that he said he has seen other math problems where you don't have enough information to solve.

Black, since iam the bus driver, the colour of my eyes are black

The prior is that his eyes are brown, since most people have brown eyes. But in the most populous countries with brown eyes and busses, the busses always have way more than 7 people on them, so that slightly shifts the probability towards non-brown colors. But even in countries where there are fewer bus passengers, most people have brown eyes, so brown is still most likely.