What to do when you can't remember a formula for a word problem?

[Tyrion101]

How do you reason it out? I get confused on problems that involve distance rate and time. What wording should I look for to tell me if s should be positive and the number should be negative or any variation in between? Should there never be a negative involving a DRT formula?

 

[phinds]

what often works is just do math that makes the units work out right.