Chapter 3 - Section 3.5 - Exponential Growth and Decay; Modeling Data - Exercise Set - Page 506: 20

Age of skeletons: about $1056$ years

Model: $ A=A_{0}e^{-0.000121t}$ Unknown: $ t $, when $ A=0.88A_{0},$ $0.88A_{0}=A_{0}e^{-0.000121t}\qquad... /\div A_{0}$ $0.88=e^{-0.000121t}\qquad.../\ln(...)$ $-0.12783=-0.000121t\qquad.../\div(-0.000121)$ $ t\approx 1056.47$ Age of skeletons: about $1056$ years