Radium Decay The amount of radium 226 remaining in a sample that originall...

Radium Decay The amount of radium 226 remaining in a sample that originally contained A grams is approximately

where t is time in years.

a. Find, to the nearest whole number, the percentage of radium 226 left in an originally pure sample after 1,000 years, 2,000 years, and 3,000 years.

b. Use a graph to estimate, to the nearest 100 years, when one half of a sample of 100 grams will have decayed.