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