Bill and amy want to ride their bikes from their neighbourhood to school which is 14.4 kilometers away. it takes amy 40 minutes to arrive at school. bill arrives 20 minutes after amy. how much faster (in meters/second) is amy’s average speed for the entire trip?

You can use the equation d=rt
Amy 14.4=40r    r=0.36 kilometers/minute
Bill 14.4=20r    r= 0.72 kilometers/minute   
Amy (0.36 kilometers/minute)(60 seconds/1000 meters)= 0.0216 meters/second
Bill (0.72 kilometers/minute)(60 seconds/1000 meters)=0.0432 meters/second

0.0432-0.0216=0.0216 meters/second faster than Amy