A collector collects stamps from foreign countries

A collector collects stamps from foreign countries. In June, she gave 20 percent of her stamps to her friend. In July, she gave 10 percent of her remaining stamps to another friend. If these were the only changes in the number of stamps in the stamp collection during those two months, what percent of her collection at the beginning of June did she give to away in June and July?

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 #12981