A candidate who gets 20% of the marks fails by 40 marks

A candidate who gets 20% of the marks fails by 40 marks. But another candidate who gets 30% marks gets 20 marks more than necessary for passing. Find the number of marks for passing?

This problem repeats another one in the library (at most with different numbers), so it's left out of browsing.

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #4460