Hamptonium is a radioactive substance that decays into two parts Monctonium and one part St. Johnite (i.e. 3 units of Hamptonium decays into 2 units of Monctonium and 1 unit of St. Johnite) . Hamptonium has a half-life of 1 million years. We find a rock that contains 20 units of Hamptonium and 40 units of Monctonium. If we assume that there was no Monctonium present when the rock was formed and no Hamptonium has been deposited in the rock since it was formed, how old is the rock.