Plz do it correctly and clear both parst A radioactive subst

Plz do it correctly and clear both parst

A radioactive substance decays in such a way that the amount of mass remaining after t days is given by the function m(t) = 13e^-0.013t where m(t) is measured in kilograms. Find the mass at time t = 0. kg How much of the mass remains after 47 days? () kg

Solution

at t=0
m(0)=13*e^(-0.013*0)
m(0)=13*e^0
m(0)=13*1
m(0)=13 mass at t=0

ii)
after 47 days
m(47)=13*e^(-0.013*47)
=13*.5428
=7.05
=7.1kg this is the mass remaining after 47 days