I guess ur just gunna have to bear with whatever until we have a multiple choice answer selection.
Step-by-step explanation:
Remember, math is a language
when you see per think fractions
15.2 miles per hour = 15.2 miles / 1 hour
since this is a fraction, Units can cancel just like numbers
To cancel miles and be left with hours rearrange the fraction
1 hour / 15.2 miles
then multiply by 72 miles

the miles cancel and youre left with hours!
so youd write and solve 72 / 15.2
B would be your best answer looking at the graphic chart
Answer:
1) Is more representative
Step-by-step explanation:
The problem with his selection is that maybe there are few students participating in certain sport and those students maybe do quite more excercise than the rest (or quite less). This will modify the results because the sample he selected is biased. This problem wont be solved by method 3 or 4, because he is still selecting students that may modify heavily the results with a high probability
This problem will also appear if he choose a sample by class. Maybe, in a class there are quite few students, and selecting from class will make those students appear quite more often than, lets say, a 7th grade student selected at random, therefore the selection is biased in this case as well.
If he has a list with all seventh grade students, each student is equallly likely to be selected and as a consequence, the the results wont be biased. Approach 1 is the best one.