Two radioactive elements X and Y have half-lives of 100 and 50 years respectively. Samples of X and Y initially contain equal number of atoms. What is the ratio of the number of the remaining atoms of X to that of Y after 200 years?
-
A.
4:1 -
B.
3:1 -
C.
1:1 -
D.
1:2 -
E.
1:4