> There is no ambiguity

Yet you give three different interpretations:

> You can find solutions for a / b / c, or b / c / a, or c / a / b

This is a clear case of ambiguity.

Even the classic question is ambiguous: "Which 3 numbers give the same result when added or multiplied together?"

Lets say the three numbers are x, y and z and the result is r. A valid interpretation would be to multiply/add every pair of numbers:

    x * y = r
    y * z = r
    x * z = r
    x + y = r
    y + z = r
    x + z = r

However, I do not think that this ambiguity is the reason why OpenAI o1 fails here. It simply started with an untractable approach to solve this problem (plugging in random numbers) and did not attempt a more promising approach because it was not trained to do so.