Answer:
0.15625 grams
Explanation:
Half life: It is related to the decay of radioactive material. The duration in which half of the material will be degraded/decayed. That means after half life 50% of the radioactive material will be left. Here the half life is 28 years.
Initial quantity of the sample: 2.5 grams.
After 28 years, the leftover quantity = 1.25 grams
After 56 years, the leftover quantity = 0.625 grams
After 84 Years, the leftover quantity = 0.3125 grams
After 112 years, the leftover quantity = 0.15625 grams