Can anyone help with this word problem?

Question

1. Molly left home and drove toward the ferry office at an average speed of 27 mph. Mark left two hours later and drove in the same direction but with an average speed of 45 mph. How long did Molly drive before Mark caught up?

 

Any assistance with this would be appreciated

Answer 1

To expand on what Kayti did. 

45x= 27x + (2*27)

45x - 27x = 54

18x=54

x= 54/18

x=3

    x + 2 =5

Molly was driving for 5 hours before Mark caught up to her.

27*5 = 45*(5-2 = 3)

  135 miles= 135 miles        

Answer 2

To solve this problem, you'll want to come up with an algebraic equation that represents how far both Molly & Mark have travelled.  Once the distance they have traveled is the same, Mark will have caught up with Molly.  We want to find out how many hours Molly had to drive to reach that distance, and we know that the time Molly has been driving is 2 hours longer than the time Mark has been driving.  

 

I'd use the following equation.

 

x = number of hours Mark has been driving

 

45x  = 27(x+2)

 

This equation shows the distance Mark has traveled (driving 45 miles per hour for x hours) equal to the distance Molly has traveled (driving 27 miles per hour for x+2 hours).  Solving for x will give you the number of hours Mark traveled, but remember to add the 2 hours to that, because we know that Mark left after Molly had already been driving for two hours.