The municipality of Randomburg provides free wifi for the citizens. Each wifi hotspot has 50m range, and they placed 3 hotspots per square kilometer randomly. At the very moment when Bob left his house, the university sent an email to all the students to notify them that all teaching activity is cancelled for today due to a bomb alarm. Bob goes to university on a straight path, and he has 70% chance to receive the notification via the free wifi on the way. How far away is Bob's house from the university?