The population in the above situation is the total number of students under Mr. Wilson.
A sample is a part of the population that may best represent the population. There is no sample in the above situation because Mr. Wilson made all students pick 5 note cards. He will be able to determine the performance of each student based on their performance in picking 5 note cards and defining the terms in each card.
She cycled 5 miles on the second day
Let x = total distance he covered
3x/4 by bus
1/2 . x/4 = x/8 by jogging
the remaining distance = x/8 by walking
thus x/8 = 800ft
x = 8 . 800 = 6400ft