Question

There was a sample of 200 milligrams of a radioactive substance to start a study. since then, the sample has decayed by 5.4% each year. let t be the number of years since the start of the study. let y be the mass of the sample in milligrams. write an exponential function showing the relationship between y and t .

Answer 1

For this case we have a function of the form:
y = A * (b) ^ t
Where,
A: initial amount
b: decrease rate
t: time
Substituting values we have:
y = 200 * (0.946) ^ t
Answer:
An exponential function showing the relationship between and and is:
y = 200 * (0.946) ^ t