dN A chemical substance has a decay rate of 9% per day. The rate of change of an amount N of the chemical after t days is given by = - 0.090N dt 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 6 days? c) What is the rate of change of the amount of the substance after 6 days? d) After how many days will half of the original 600 g of the substance remain? a) N(t)= b) After 6 days, g will remain. (Round to the nearest whole number as needed ) c) After 6 days, the rate of change is g/day (Round to one decimal place as needed.) d) Half of the substance will remain after days (Round to one decimal place as needed )