Question

Situation:
A 25 gram sample of a substance used for drug research has a k-value of 0.1205.
N=N0e^-kt
N0= initial mass(at time t=0)
N= mass at a time t
K= a positive constant that depends on the substance itself and on the units used to measure time
T=time, in days
Find the substances half-life, in days. Round your answer to the nearest tenth?????