I bought two books; for Rs

I bought two books; for Rs. 480. I sold one at a gain of 10% and other at a gain of 20% and then I found each book was sold at the same price. Find the cost of the book sold at a lesser gain ?

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #26784