Please help with all the parts of the question

A chemical substance has a decay rate of 8% per day. The rate of change of an amount N of the chemical after t days IN is given by - 0.080N. a) Let No 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