Achemical substance has a decay rate of 7.7% per day. The rate of change of an amount N of the chemical after t days is given by E = 0.077N. a) Let N0 represent the amount of the substance present at t = 0. Find the exponential function that models the decay. b) Suppose that 600 g of the substance is present at t = 0. How much will remain after 3 days? c) What is the rate of change of the amount of the substance after 3 days? d) After how many days will half of the original 600 g of the substance remain