For a certain travel route

MATHEMATICS · Subjective · CBSE · Mathematics · Continuity and Differentiability · Continuity and Differentiability

Problem

For a certain travel route, the total time (in hours) as a function of a decision variable

d

(in miles) is

T(d)=\frac{d}{5}+\frac{\sqrt{(60-d)^2+144}}{3}.

Compute

T'(20)

and state whether the total travel time is increasing or decreasing at

d=20\text{ mi}