Is this a solid way to mark an exam on a Mathematical subject?

[cdux]

In an Engineering course I was used to being rewarded for proving a good understanding of theory. For example, if I explained a basis of the following solution, it would still give some rewards, even if the solution itself had major computing errors or even if it was partially mathematically wrong.

On my last exam on a Mathematical subject (based on a non-Engineering Mathematics department) I was given a 20% when I expected around 50-60%. My understanding is that they rewarded 0% to the theory preceding a solution, if the solution was at least partially mathematically incorrect.

Is that fair or normal?

I suspect that it's not "illegal", but I believe it stretches the lengths of lack of leniency. I'm sure they could prove it's legit to their colleagues but at the same time it's a bit extreme that I suspect they could even get away with a 70%. So with a wiggle room between 20-30% and 60-70%, it seems a bit extreme going for the lowest end.

Then again, I almost hope I'm not right since it would mean I'm not 'targetted', or at least the whole class isn't ('cause it was probably relatively consistent)

 

[Vanadium 50]

A legendary engineering professor once said "Make a sign error, build bridge upside down, and people and cars fall off. No credit."