When Metin’s phone is fully charged, it runs out in 32 hours if he only uses it for phone-calls, in 20 hours if he only uses it for the internet, and in 80 hours if he does not use it at all. Metin gets on a train with his phone half-charged. While on the train, the time he is on the internet, the time he is making phone-calls and the time he is not using it are all the same. His phone runs out of charge just as the train reaches his destination. How many hours did the train journey take?