The half-life of a radioactive substance refers to the amount of time it will take for the quantity to decay a half as much as it was originally. Substance Q has a half-life of 20 years. If in 2015,...

The half-life of a radioactive substance refers to the amount of time it will take for the
quantity to decay a half as much as it was originally. Substance Q has a half-life of 20
years. If in 2015, 100g of Q was at hand, how much will be at hand in 2055? How much
will be at hand in 2060?