Geology (and other Earth Sciences)

1. A hypothetical rock is going to be analyzed for its radioactive isotope contents, X and Y. X is the parent and Y is the daughter isotope. Assume that the half-life of the radioactive isotopes is 10,000 years. Based on this information, answer the following two questions.
A) How much of the parent (X) and how much of the daughter (Y) will be present at the time the rock forms? You can give your answer in % as follows: (12 points)
X = ____% ; Y = ____ %
B) How much of the parent (X) and how much of the daughter (Y) will be present after 10,000 years? You can give your answer in %. as follows: (13 points)
X = ____% ; Y = ____ %