Joe’s average (arithmetic mean) test score across 4 equally weighted tests was…

Joe’s average (arithmetic mean) test score across 4 equally weighted tests was 40. He was allowed to drop his lowest score. After doing so, his average test score improved to 45. What is the lowest test score that was dropped?

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 #34131