Can someone help me pls

50 years

12.5 g

2.5 g

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