Question 1170476
At time 0, distance from son is 200 miles.
At time {{{60*t=200}}}, t, distance from son is 0 miles.-----but this not necessary.


{{{t=200/60=20/6=10/3}}} or {{{3&1/3}}}{{{hours}}}


The vertical axis intercept was already described,  (0,200); 


{{{highlight(y=-60x+200)}}}