An isotope has a mass of 120 mg after 2 days and 75 mg after 9 days

MATHEMATICS · Single correct · AP · Calculus AB · Differential Equations · Differential Equations

Problem

An isotope has a mass of 120 mg after 2 days and 75 mg after 9 days. If the decay is exponential, which value best approximates the decay constant

k

(in day

^{-1}

)? (a)

0.067

(b)

-0.078

(c)

-0.067

(d)

-0.029