A trader marks his books 30% more than the cost price

A trader marks his books 30% more than the cost price. If he allows 20% discount, then find his gain or loss percent?

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 #38194