A and B complete a work in 50 days

A and B complete a work in 50 days. A alone can do it in 40 days. If both together can do the work in how many days?

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 #34136