Posted by Jerald on Tuesday, November 12, 2013 at 8:54pm.
Mark and Sandy are participating in a BikeaThon for charity. Mark oversleeps, so Sandy gets a one hour head start and bikes at a speed of 12 miles per hour. To catch up to Sandy, Mark decides that he needs to bike at a speed of 15 miles per hour.
1. Make a chart that shows how far Mark and SAndy ride their bikes during the first three hours of the Bike a thon
Hour 1: Mark 15mph Sandy 12mph
Hour 2: Mark 30mph Sandy 24mph
Hour 3: Mark 45mph Sandy 36mph

Math  Ms. Sue, Tuesday, November 12, 2013 at 8:59pm
You missed the fact that Sandy had a one hour head start.
At the end of:
Hour 1: Sandy  12 m; Mark 0
Hour 2: Sandy  24 m; Mark 15
Hour 3: Sandy  26 m; Mark 30 
Math  Jerald, Tuesday, November 12, 2013 at 9:03pm
Thank you.
2. WRite an expression that represents Sandy's journey. Be sure to define your variables
t=hour
12t + 12 
Math  Ms. Sue, Tuesday, November 12, 2013 at 9:09pm
You're welcome.
12t 
Math  Jerald, Tuesday, November 12, 2013 at 9:16pm
But didn't she have a one hour head start so she would have had an extra 12 m?

Math  Ms. Sue, Tuesday, November 12, 2013 at 9:28pm
You just need an expression that represents her journey. It doesn't make any difference what time she started.