Question

The halflife of a radioactive radium is 1620 years. What percent of a present amount of radioactive radium will remain after 100 years?

Answer 1

every 1620 years, the amount decreases by 1/2

so 2^-(t/1620)

Answer 2

t would be the amount of years, so when t = 0, then 2^-(t/1620)= 1

when t=1620, then 2^-(t/1620)= 1/2, and so on and so forth

so now solve for when t=100