The cost of an article is decreased by 20%

The cost of an article is decreased by 20%. If the original cost is $40, find the decrease cost.

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 #7666