3. Let each shake of the pennies or thumbtacks represent 1 year. What is the half-life, in years, for the pennies in experiment 1? What is the half-ife, in years, for the
thumbtacks in experiment 2?

In experiment 1 it starts with 200 pennies and after one half life, 95 stable pennies are taken out.

In experiment 2 it starts with 50 thumbtacks and after one half life 12 stable ones are taken out.