Question

Q(t)= mathcal Q 0 e^ -kt may The function be used to model radioactive decay . Q represents the quantity remaining after tyears;k is the decay constant, 0.00011. How long, in years, will it take for a quantity of plutonium-240 to decay to 25% of its original amount? O O 9,450 years 3, 150y years C. 12, 600 years D. 1, 5 years

Answer 1

@ramen

Answer 2

To solve this we can clear up some junk. So our equation is
Q(t) = Qo e^-kt
plug in 0.00011 for k
and the initial amount for Qo is 1, which is the starting value.
25% = 1/4
So 1/4 = 1e^-0.00011x
Use a graphing calculator to estimate

Answer 3

If you want to do it the non-graphing calculator way, Use natural log

Answer 4

If you want to learn how to do it the natural log way, Ask away!