A Radioactive Substance Decays in Such a Way That the Amount

Multiple Choice

A radioactive substance decays in such a way that the amount of mass remaining after t days is given by the function $m ( t ) = 13 e ^ { - 0.015 t }$ where $m ( \text { t })$ Is measured in kilograms. Round your answers to three decimal places. Find the mass at time $t = 0$

A) $13.5 \mathrm {~kg}$
B) $0.015 \mathrm {~kg}$
C) $13.015 \mathrm {~kg}$
D) $15.135 \mathrm {~kg}$
E) none of these