Precalculus (6th Edition) Blitzer

Published by Pearson
ISBN 10: 0-13446-914-3
ISBN 13: 978-0-13446-914-0

Chapter 3 - Section 3.5 - Exponential Growth and Decay; Modeling Data - Exercise Set - Page 507: 46


$56$ years old.

Work Step by Step

Let $P(x)=70$; we have $\frac{90}{1+271e^{-0.122x}}=70$ and $271e^{-0.122x}=\frac{90}{70}-1\approx0.2857$ Thus $x=-\frac{ln(0.2857/271)}{0.122}\approx56$ years old.
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.