Question

The half life of radon 222 is 3.82 days. If the initial mass of a sample of radon 222 is 198.72 grams, how much will remain after 19.25 days?

Answer 1

after t days, the amount remaining will be

198.72 * (1/2)^(t/3.82)

Now just plug in the number of days you need.

Answer 2

Yes