math
posted by Anonymous .
The mass m(t) remaining after t days from a 70 g sample of thorium234 is given by the equation shown below.
m(t) = 70e0.0274t
Find the halflife of thorium234. (Round your answer to the nearest tenth.)

you would be solving
35 = 70 e^.0274t
.5 = e^.0274t
.0274t = ln(.5)
t = ln(.5)/.0274
= 25.297
half life is appr 25.3 years