Question 134609
How long is the track? 400
How many laps has the runner already run? 2
The equation is asking for the total distance.
That distance is the distance already run + the distance run as time increases
 
{{{Distance = DistanceRunAtTimeZero + speed*t}}}
{{{D = (2*400) + 3t}}}
{{{D = 800 + 3t}}}