Group C ran more miles an individual.
Explanation: To find the number of miles per individual, you must subtract the total number of miles by the total number of people who ran those miles. Which ever answer is larger, tells us which group ran more miles an individual.
Here are the calculations-
Group C: 27/4=6.75
Group D: 39/6=6.5
As you can see, Group C ran more miles an individual than Group D.
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