Start with trying to figure out rate (r): P = i•e^rt 5200 = 4000•e^(r•7) 5200/4000 = 1.3 = e^7r ln 1.3 = ln (e^7r) .262 = 7r•1, because the ln (e) = 1 r = .262/7 = .0375 Now that you have the rate, plug in that for r and 9 hours as the new t, with again our 4200 as the i P = i•e^rt = 4200•e^(.0375•9) P = 4200•1.401 = 5,886 bacteria
