Question 659239
It is standard practice to use the following variables in distance problems
(1) d = distance
(2) r = rate
(3) t = time
Us math wizards however, must be careful that the proper units of these three variables are consistant. Don't worry, I'll show you on each example.
There are three forms of the formula:
(4) d = r*t
(5) r = d/t and
(6) t = d/r
Now let's do your problems.
In (a) you want the time so use (6) to get
(7) t = d/r
(8) t = 13.5/3 or
(9) t = 4.5 hr
I'll finish later, gotta go to soccer game