Problem 42 (p.228) Different radioisotopes have different half-lives. For example, the half-life of carbon-14 is 5700 years, the half-life of uranium-235 is 704 million years , the half-life of potassium-40 is 1.3 billion years, and the half-life of rubidium-87 is 49 billion years.

Why would an isotope with a half life like that of carbon-14 be a poor choice to get the age of the Solar System?

b) The age of the universe is approximately 14 billion years. Does that mean that no
rubidium-87 has decayed yet?