8. Ming left home and drove toward the ocean. Norachai left one hour later driving at 45
mph in an effort to catch up to Ming. After driving for four hours Norachai finally
caught up. What was Ming’s average speed?
Rate Time Distance


  1. Ming’s average speed is 36mph
    Let the average speed of Ming’s be x mph.
    Given that, Norachai average speed = 45 mph
                         Time taken by Norachai to catch up to Ming =  4 hrs  
    As Norachai left after 1 hour and reached after 4 hour to reach Ming
    Therefore, Ming took 5hrs. (1 + 4 hrs.) to reach the ocean.
    As both were going to the same destination they would be covering same distance.
                 Distance covered by Ming = Distance covered by Norachai
                          x * 5 = 45 * 4
    As,    distance = speed * time
    Then from equation (1) we get,
                            x = 180/5
                            x = 36
    Hence, average speed of Ming’s is 36mph                  
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