The half-life of a certain radioactive material is 75 days. An initial amount of the material has a mass of 381 kg. How do you write an exponential function that models the decay of this material and how much radioactive material remains after 15 days?

1 Answer
Feb 27, 2018

Half life:

y=x*(1/2)^t with x as the initial amount, t as "time"/"half life", and y as the final amount. To find the answer, plug in the formula:

y=381*(1/2)^(15/75)=>

y=381*0.87055056329=>

y=331.679764616

The answer is approximately 331.68