Question

A sample of a radioactive isotope had an initial mass of 700 mg in the year 1991 and decays exponentially over time. A measurement in the year 1996 found that the sample's mass had decayed to 210 mg. What would be the expected mass of the sample in the year 2003, to the nearest whole number?

Answer 1

Answer: 678

Explanation:

Answer 2

39

Explanation:

a(b)^t=y

210=700(b)^5

b=0.78600308...

2003-1991= 12 years

700(0.78600308)^12=38.92145026

rounded to the nearest whole number = 39

hope this helps!