posted by Rob .
assume that a particular radioactive-isotope has a half-life of 100 million years. Also assume that the parent isotope is incorporated into the minerals found in igneous rocks and that the only daughter atoms in the rock formed from the decay of the parent isotope. Measurements show that one mineral in the igneous rock contains 5 million atoms of the parent isotope and 35 million atoms of daughter.
a) what is the age of this mineral in years?
b) what is the age of rock?