How would we calculate the distance covered by a train that starts at rest, then accelerates to 5km/hr in 30 mins then stays at this constant speed for 12 minutes?

I would draw the situation Then use bring out the relevant SUVAT equationsI would explain how the equations work to give the student some intuitionThen carry out the problem step by stepThen I would ask if they'd like to go through a similar problem by themselves, aiding them if needed.