## anonymous 5 years ago Situation: A 15 gram sample of a substance that's a by-product of fireworks has a k-value of .1405. find the substance's half-life, in days. round to the nearest tenth

1. anonymous

2. anonymous

$f(t) = A*e^{-kt}$ if f(t)/A = .5: $.5 = e^{-kt}; -kt = \ln (.5); t = \ln(.5)/-k = 4.9 days$

3. anonymous