Active virus is subject to decay with a rate constant of, kd = 2.2 day-1 at 37 C and 0.76 day-1 at 31 C. The production rate of virus from a packaging cell line is kp = 3.3 virus/cell-day at 37 C and kp = 2.9 virus/cell- day at 31 C. Assume there are 1x106 cells, and the volume of liquid medium is 2 mL. The initial number of virus in solution is zero. How many viruses are there per mL 12 h after initiation of virus production