The concentration (in mg/L) of a substance in a tank is modeled by

MATHEMATICS · Single correct · AP · AP Precalculus · Exponential and Logarithmic Functions · Exponential and Logarithmic Functions

Problem

The concentration

C

(in mg/L) of a substance in a tank is modeled by

C=C_0 e^{0.25 t}

, where

t

is measured in hours. If

C=120\text{ mg/L}

after

4

hours, what is the initial concentration

C_0

? (a)

120\text{ mg/L}

(b)

44\text{ mg/L}

(c)

60\text{ mg/L}

(d)

326\text{ mg/L}