An aircraft company has 20 planes in its fleet

An aircraft company has 20 planes in its fleet. Every year it retires 5 of its planes and replaces then with 6 newer planes. How many years will it take the company, starting from 2010, to reduce the number of it s old planes to less than half of its fleet?

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #79622