The amount of a radioactive substance decreases exponentially, with a decay constant of 3% per month.
(a) Write a differential equation to express the rate of change.
(b) Find a general solution to the differential equation from part (a).
(c) If there are 75 g at the start of the decay process, find a particular solution for the differential equation from part (a).
(d) Find the amount left after 10 months.