Imagine you are dating a mineral sample that contains one-eighth of its original parent isotope. What is the absolute age of the sample if the half-life of the parent isotope is 15 years?
A. 1.875 years
B. 23 years
C. 45 years
D. 120 years

Arailroad car collides with and sticks to an identical railroad car that is initially at rest. after the collision, the total kinetic energy of the two cars is a) the same as before. b) half as much as before. c) one third as much as before. d) one fourth as much as before. e) twice as much as before.