It takes 3 workers a total of 12 hours to build a…

It takes 3 workers a total of 12 hours to build a giant machine with each worker working at the same rate. If 4 workers start to build the machine at 11:00 AM, and one extra worker per hour is added beginning at 3:00 PM, at what time will the machine be complete?

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 #8739