Answer:
1.1289 grams ( approx )
Step-by-step explanation:
Since, the final quantity of an element which has half life of n periods,
Where,
P = initial quantity,
t = total number of periods,
Here, A = 1 gram, t = 1000 years, n = 5715 years,
By substituting the values,
( using calculator )
Hence, the initial quantity would be 1.1289 grams ( approx )