IM ON 19 OF 42 QS CAN SOMEONE DIRECT MESSAGE ME SO I DONT USE ALL MY POINTS.

The amount of a sample remaining after t days is given by the equation where A is the initial amount of the sample and h is the half-life, in days, of the substance. A sample contains 18% of its original amount of Radon-222. The half-life of Radon-222 is about 3.8 days. Which is the best estimate for the age of the sample?
1.5 days
2.5 days
9.4 days
21.1 days