An element with mass 310 grams decays by 8.9% per minute. How much of the element is remaining after 19 minutes, to the nearest 10th of a gram?

Question

An element with mass 310 grams decays by 8.9% per minute. How much of the element is remaining after 19 minutes, to the nearest 10th of a gram?

Answer 1

This is an exponential decay problem:

A(t) = A₀·b^t

1. A(t) = amount of the element left after t minutes
2. A₀ = initial amount of the element = 310 g
3. b = growth/decay factor = (1 - rate) = (1 - 0.089)
4. t = minutes = 19

Plug the numbers into the formula and use your calculator to compute the answer.