eric

Eric the Red and his father, Thorvald, were some pretty rough customers. It seems that they got themselves into trouble in Norway around the year 1000. They had to leave the country, so they headed off to Iceland.

Iceland was fully settled by this time, so it wasn't long before the two adventurers were back in trouble!

Needing a new place to run to, and acting on a rumor that there was land to the west of Iceland, Eric sailed off and discovered Greenland.

The first person who saw Greenland told 2 people about it the day he saw it.

The next day, those 2 people each told 2 more people, and the next day, those 4 people each told 2 more people, and so it went.

If Eric the Red was the last person in Iceland to hear the rumor about Greenland, how many days after the rumor started did he hear about it? At that time, Iceland had a population of 20,000.