Learning Resources

Investigation 1: Did Mr. Lam Speed?

Test yourself (Answers)

1. In the first time period the distance traveled is greater than the time, which means that the speed would be greater than 1 km/min. For the second time period they are equal, which would mean that the speed is 1 km/min. For the third, the speed would be greater than 1 km/min since the distance is greater than the time. So the average speed decreases in the second leg of the trip and then increases again.
   
   
2. Using the formula   , we can calculate each average speed or rate:

   First time period:  

   Second time period:  

   Third time period:  

    

3. The average speed for the entire trip is:
   
    
   
   
4. The overall average speed makes sense since the three partial speeds range from 60 km/hr to 80 km/hr, the overall average should fall within that range, which it does.