By selling 8 pens for a rupee a woman loses 25%

By selling 8 pens for a rupee a woman loses 25%. How many for a rupee should he sell in order to gain 25%?

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 #45330