Junior Johnson won with an average speed of 125 miles per hour. The next year Marvin Panch won with an average speed of 150 miles per hour. What was the differ

Question

Junior Johnson won with an average speed of 125 miles per hour. The next year Marvin Panch won with an average speed of 150 miles per hour. What was the difference in the race time between 1960 and 1961 (in hours)?

Answer 1

Melissa:

You will need the race distance to solve this question.

 

The time for each racer is the race distance divided by the average speed.  Find the time for each racer, then take the difference.  Make sure the units are the same!  You will need the race distance in miles to find the time difference in hours.

Answer 2

Well, with the extra information that Junior Johnson won the Daytona 500 (a 500 mile race) in 1960 and Marvin Panch won it is 1961 (I didn't double check the times; per Wikipedia).

 

The problem compares hours:     500 miles / (125 miles/hour)      and 500 mile / (150 miles/hour)

  To divide, invert and multiply:

                                             500/125   hours         versus     500 / 150 hours      [note: miles cancel]

 

                                                4 hours                 versus      3.33 hours = 3 hours 20 minutes

The difference (in hours) ie:

             2/3 hour     (which is 40 minutes)