Answer:
218.29 years
Explanation:
Initial Concentration = 100%
Final Concentration = 93.79%
Half life = 5730 years
Time = ?
Decays are first ordeer reactions, we have;
t1/2 = 0.693 / k
k = 0.693 / t1/2
k = 0.00012094 y-1
From the integrated rate law of first order reactions;
ln[A] = ln[A]o - kt
kt = ln[A]o - ln[A]
kt = ln(0.9739) - ln(1)
kt = 0.0264
t = 0.0264 / 0.00012094
t = 218.29 years