Answer:
50 years
12.5 g
2.5 g
Step-by-step explanation:
The half-life is the time it takes for the sample to become half of the original. At 0 years, none of the sample has decayed. At 50 years, half of the sample has decayed. This means that the half-life is 50 years.
If you look at the diagram, at 150 years, you will have 1/8 of the original amount. If you start with 100 g, you will have 12.5 g after 150 years.
100/8 = 12.5
Looking at the diagram, you can see that at 100 years, you will have 1/4 of the original amount. If you start with 10 g, you will have 2.5 g after 100 years.
10/4 = 2.5