Suppose a laboratory has a 61 g sample of polonium-210. The half-life of polonium-210 is about 138 days.
a. How many half-lives of polonium-210 occur in 828 days?
b. How much polonium is in the sample 828 days later?

A. 6; 10.17 g

B. 6; 0.95 g

C. 6; 4,209 g

D. 6; 0.48 g