Lindsay can paint 1/x of a certain room in 15 minutes

Lindsay can paint 1/x of a certain room in 15 minutes. What fraction of the same room can Joseph paint in 15 minutes if the two of them can paint the room in an hour, working together at their respective rates?

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 #67061