Robert's salary was decreased by 50% and subsequently increased by 50%

Robert's salary was decreased by 50% and subsequently increased by 50%. how much percentage does he lose?

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 #12754