We'll use these numbers later to mathematically model the "decay" of the class' M&M™s.
In this case, R0 is the initial rate of decays per second at t = 0. We can use a Wolfram Mathematica template with our M&M™ data to find an expression for the decay constant λ, which for a statistically large sample is the probability that a given single M&M™ will decay in a given time interval.
Related to decay constant λ is the time constant τ, which for a statistically large sample is approximately the average lifetime of a given single M&M™ before it decays (that is, eaten). (This is not one toss interval--can you explain why? And it is not merely because your class' sample of M&M™s may not be statistically large.)
Each time interval on the clock displayed here is one half-life for the radioactive atoms to decay into a daughter atom (light gray squares). After one half-life, one-half of the original radioactive atoms remain; after two half-lives, one-quarter of the original radioactive atoms remain; so after three half-lives, one-eighth of the radioactive atoms remain. The key to determining the radioactive age of this substance is to assume that it started out with radioactive atoms with no daughter atoms (disregarding the amount of inert material), so the greater proportion of daughter atoms to radioactive atoms corresponds to an older sample.
Note that after a molten sample solidifies, it will start anew with having radioactive atoms with no daughter atoms. So, melting a sample "resets" its solidification age--how long ago has it been since the sample started with radioactive atoms with no daughter atoms.