Keeping Pace - A Balanced Assessment Task

Topic:
Algebra
BLUE & GREEN started from the same point at the same time down the same path to school. GREEN decided to walk at a fast pace for half the distance and at a slow pace for half of the distance. BLUE decided to walk at fast pace half the time and at a slow pace half the time. [You can use the GREEN dots to set fast and slow paces. You can use the BLUE dot to set the total time blue takes to get to school.] Under what circumstances does GREEN get to school first? who gets to the halfway point first? Under what circumstances does BLUE get to school first? who gets to the halfway point first? Do they ever meet on the way to school? What questions could / would you put to your students based on this applet ?