An investment of …10000 increased to …10000 have increased to $80000 by…

An investment of $10000 was made in a certain account and earned interest that was compounded annually. The annual interest rate was fixed for the duration of the investment, and after 12 years the $10000 increased to $40000 by earning interest. In how many years after the initial investment was made the $10000 have increased to $80000 by earning interest at that rate?

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 #60453