Question

exponential decay anyone?

Answer 1

post the question..

Answer 2

wait actually i gtg.. but post it anyway maybe someone will help..

Answer 3

ok :)

Answer 4

You need to invert the equation to find the solution.
N/N(0) = exp(-kt) = 0.7
(-kt) = log(0.7)
t = -1/k*log(0.7) = 3567 years