Question

The amount of radioactive element remaining, r, in a 100mg sample after d days is represented using the equation r=100(1/2) d/5. What is the daily percent of decrease

Answer 1

12.94%

Explanation:

r = 100(1/2)^(d/5) = 100((1/2)^(1/5))^d ≈ 100(.87055)^d

The daily decrease is 1 - 0.87055 = 0.12944 ≈ 12.94%