Application of Derivatives Part 2

A hostel has 100 students. On a certain day (consider it day zero) it was found that two students are infected with some virus. Assume that the rate at which the virus spreads is directly proportional to the product of the number of infected students and the number of non-infected students. If the number of infected students on 4‌th ‌ day is 30 , then number of infected students on 8‌th ‌ day will be____