1. The problem statement, all variables and given/known data http://imgur.com/aYCc9 also in attachment 2. Relevant equations n/a 3. The attempt at a solution I'm not sure how to tell when distance is proportional to time. My guess is it would be graphs a and b because they're both straight lines and when time increases, distance increases a set amount as well. Also can you explain why the curve function does not have distance proportionate to time?