Suppose an isotope has a half-life of 50 million years, and 1\8 of the sample remaining consists of that isotope. What is the age of the rock from which it was taken?
A)150 million years
B)300 million years
C)400 million years
D)600 million years
E)800 million years

Question

Quizplus · Accepted Answer

150 million yearsIf 1/8 of the sample remains, it means the sample has gone through three half-lives (since 1/2 to 1/4 to 1/8). Each half-life is 50 million years, so 3 half-lives would be 150 million years.

Suppose an Isotope Has a Half-Life of 50 Million Years