10 xy + 3y + 20 ax + 6a = y(10x+3) + a(20x+6) = y(10x+3)+2a(10x+6)=
(y+2a)(10x+3)
We are given a line segment with two points on each end. Rebecca draws two arcs with equal radius from each point. Now, the intersection of the two arcs is the midpoint of the line. This can be explained by the radius of the arcs. Since they are equal, meaning they have the same distance from each point. Thus, the midpoint of the line.
There are 2001 items in that set.
So n(A) = 2001
We can individually count them all out, which is very slow and tedious, or we can use the formula
n-m+1
where,
m = starting value
n = ending value
In this case,
m = 0
n = 2000
So,
n-m+1 = 2000-0+1 = 2001
This formula only works if we increase the number by 1 each time (eg: 6, 7, 8, etc)
The sample % of these two populations would be 100/size (of student body at each school) x 100 so this would compare the two student bodies preferences for the particular type of candy bar. However, the actual % of the whole student body at each school would be a factor also. If the high school only had 200 students then this would be 50% representative but if the middle school had say 500 students this would only be 20% representative so this would have to be taken into account too. It might be more representative to have the same % of the student bodies respectively for the sample.