We write the generic exponential equation: y = A (b) ^ t Where, A: initial population B: growth rate t: time in hours. Substituting values we have: y = 5 (2) ^ ((1 / 1.5) * t) For t = 9 hours we have: y = 5 (2) ^ ((1 / 1.5) * 9) y = 320 million For t = 24 hours (one day) we have: y = 5 (2) ^ ((1 / 1.5) * 24) y = 327680 million For t = 2 hours we have: y = 5 (2) ^ ((1 / 1.5) * 2) y = 12.5992105 million Answer: a) t hours? y = 5 (2) ^ ((1 / 1.5) * t) b) 9 hours? y = 320 million c) 1 day? y = 327680 million d) 2 hours? y = 12.5992105 million