Two numbers are respectively 20% and 50% more than a third number

Two numbers are respectively 20% and 50% more than a third number. The percentage that is first of the second is?

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 #1915