3. Given a 3-compartment first-order kinetic model, and ending with 1015 atoms of the 2nd progeny (3'd compartment) after 100 hours, use Bateman equations to predict the number of atoms in the 1st compartment at time zero. The half-life of transfer from the 1st to 2nd compartment is 15 hours, the half-life of transfer from the 2nd to 3'd compartment is 30 hours, and the half-life of transfer out of the 3d compartment is 25 hours. [20 pts - 5 pts for correctly setting up the Bateman equation, 10 pts for setting up the equations for the three compartments correctly and 5 pts for the correct answer]