Based on the Information in the Graph,approximately How Old Are

Multiple Choice

Based on the information in the graph,approximately how old are two rocks,one containing 25% uranium-238 and 75% lead,and one containing 50% uranium-238 and 50% lead?

A) around 2.25 billion years and 4.5 billion years,respectively
B) around 9 billion years and 4.5 billion years,respectively
C) around 1.3 billion years and 2.4 billion years,respectively
D) around 4.5 billion years and 9 billion years,respectively
E) The question cannot be answered with the information provided.