A train running at 1/3 of its own speed reached a place…

A train running at 1/3 of its own speed reached a place in 9 hours. How much time could be saved if the train would have run at its own speed?

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 #6244