A pupil's marks were wrongly entered as 83 instead of 53

A pupil's marks were wrongly entered as 83 instead of 53. Due to the average marks for the class got increased by half. The number of pupils in the class is?

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 #61629