A dishonest grocer professes to sell pure butter at cost price, but…

A dishonest grocer professes to sell pure butter at cost price, but he mixes it with adulterated fat and thereby gains 20%. Find the percentage of adulterated fat in the mixture assuming that adulterated fat is freely available?

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 #25158