A bacteria culture grows with constant relative growth rate. The bacteria count was 1,920 after 4 hours and 1,966,080 after 12 hours. (a) What is the relative growth rate? Express your answer as a percentage. (Round your answer to two decimal places.) 86.64 % per hr (b) What was the initial size of the culture? 60 bacteria (c) Find an expression for the exact number of bacteria after t hours, y(t). y(t) = 60e (In(1024) (d) Find the number of bacteria after 10.5 hours. (Round your answer to the nearest whole number.) X bacteria (e) Find the rate of growth (in bacteria per hour) after 10.5 hours. (Round your answer to the nearest whole number.) bacteria per hour (f) How many hours did it take for the population to reach 72,000? (Round your answer to two decimal places.) hr