Question 201484
20 = 50 e^(-.024755 t)


dividing by 50 ___ .4 = e^(-.024755 t)


taking natural log ___ ln(.4) = -.024755 t


dividing by -.024755 ___ [ln(.4)] / -.024755 = t



you can do this on your calculator ___ it should have a natural log (ln) key