Tiffany is monitoring the decay of two radioactive compounds in test tubes at her lab. Compound A is continuously decaying at a rate of 12% and compound B is continuously decaying at a rate of 18%. Tiffany started with 30 grams of compound A and 40 grams of compound B. Create a system of inequalities that can be used to determine when both compounds will be less than or equal to the same mass, M, where t is time, in weeks, PA is the initial amount of compound A, PB is the initial amount of compound B, and r is the rate of decay.

Enter the inequalities in the field by replacing the values of PA, PB, and r.