M, N and O can do a piece of work in 60…

M, N and O can do a piece of work in 60, 30 and 20 days respectively. Inhow many days can M do the work if he is assisted by N and O on every third day?

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #19397