A certain culture of bacteria quadruples every hour

A certain culture of bacteria quadruples every hour. If a container with these bacteria was half full at 7:00 a.m., at what time was it one-eighth full?

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 #7758