Assume two individuals, \(A\) and \(B\), are traveling by car and initially are
400 miles apart. They travel toward each other, pass and then continue on.
a. If \(A\) is traveling at 60 miles per hour, and \(B\) is traveling at \(40
\mathrm{mph},\) write two functions, \(d_{\mathrm{A}}(t)\) and
\(d_{\mathrm{B}}(t),\) that describe the distance (in miles) that \(\mathrm{A}\)
and \(\mathrm{B}\) each has traveled over time \(t\) (in hours).
b. Now construct a function for the distance \(D_{\mathrm{AB}}(t)\) between A
and \(B\) at time \(t\) (in hours). Graph the function for \(0 \leq t \leq 8\)
hours.